Demonstration I.
Of the Bones in General.

THE Doctrine of the Bones in General, What to be consider'd in the Bones in General. consists in these Eleven Things, as Defini­tion, Substance, Composi­tion, manner of Ossification, Vessels, Nourishment, Differences, Parts, or Things to be consider'd in the Bones; [Page 2] together with their manner of Arti­culation, Number and Use; of all which in order.

Galen defin'd a Bone to be the most hard, Antient De­finition. firm, and terrestrious part of all the Body. Laurentius adds, and says, That it's ingendred by the for­mative Faculty, by reason of great heat, out of the most crass and ter­restrious part of the Semen, to serve as a Foundation to all the Body, and to give it Shape and Figure; but this Definition, as it is not compleat e­nough, so on the other hand, the word Faculty, is a Term which they used to exprese themselves by, when they were at a loss for an Answer or Solution to any Question proposed; besides, it's not at all agreeable to the Idea we have of the formation of the Bones, or Use; yet it's certain the Antients made use of that Term to ex­plain most of the Actions of the Bo­dy; for when they were to declare how the Chyle, or Blood was made, or how the Bones or Cartilages were form'd, nay, how the Senses acted; they answer'd, That the Stomach had [Page 3] a Chylific Faculty, the Liver a San­guifying; the Bones were form'd by an Ossific, and the Cartilages by a Cartilaginous Faculty, that the Eye saw by the Visive Faculty; &c sic de caeteris.

This was a general Answer, by which they eluded (as well by their occult Qualities) all Difficulties pro­posed to them, so that their Pupils were as Ignorant at the finishing of their Studies▪ as at the beginning; but we at this Day explain all these Actions purely Mechanically; as I shall shew in demonstrating each part of the Osteology exactly, that the Action which it performs, abso­lutely depends on its Structure, so that it can do nought else, but what it does.

But to return from whence I have digress'd; Modern Definition. the Moderns say a Bone is a similer part, most dry, cold and hard, without sense, (unless by some Preternatural Accident) inflexible, affording Stabiliment, Figure and Form to the whole Body.

[Page 4] A Bone may be consider'd at two distinct times, either before or after the Birth.

In their beginning, Nature and Substance. or before the Birth, they are of a Membranous Sub­stance, wrapt up, as it were, in very many folds, or Laminae; which at first are Gelatinous, in time grow Cartilaginous, and at last when suffi­ciently indurated by the Ossific Li­quor, are so strong as to resist all in­ward force, and their Parts which had before some Heterogeneous Bo­dies in their Insterstices, being squee­zed closer by the power and pressure of the Spirits, dis-engage themselves from those Bodies which lye between their Laminae, so grow more solid, wholly fixt, and void of motion, which is about the time when the Bones have attain'd their full perfe­ction of growth, which also puts a period to the bulk and magnitude of the Body, so that they are no more extended or enlarged, either in breadth or length.

The Bones are composed of many strings, Composition of stringy Fibrils. or threads, which have their [Page 5] course according to the length of the Bones, or their Figure; for if the Bone be of an unequal, or irregular Figure, the strings are also unequal, and irregular; except in the Cranium, where the threads begin at a point, (sometimes two or more) for the most part in the Centre, and termi­nate in the Circumference of the Bone, as the Spokes in a Wheel; for which reason it's more thick, and compact there, than in the Circumference, the thready Fibrils being more close and united there, which is visible in the Cranium of a Foetus; the Bones have also some transverse Fibres, to hold the long ones in; which may be seen in the Bones of the Tarsus, as al­so in the Extremities of most of the long Bones, where the Porosities are.

The Ossification begins not in the same place of every Bone; Where the Ossification begins. in the long Bones it begins in the middle, and to­wards each end; but in Bones of an irregular Figure in several places, as may be seen in the Ossa Innominata of a Foetus, where it begins at three points or places at once, so that they [Page 6] seem to be three distinct Bones united just in the middle of the Acetabulum, but in time, as the Ossification in­creases, they grow more strong, the fibrous threads join, and so make but one Bone; for if the Bones should have been totally Ossified before the Birth, Why the Bones are not totally Ossified be­fore the Birth. how should the Foetus pass through the Vagina of the Womb as it doth? For it's without Dispute, that both the Bones of the Head, and also the Hips of the Foetus, give way some­what in time of Exclusion; for it's observed that those Animals which have long and small Heads, ☜ but big Bodies, have the Bones of their Head wholly Ossified before the Birth, but their Ribs not, so careful is Nature in this Affair.

In the Skull, and most broad thin Bones, as the Sternon, the Ossificati­on begins at two, three, or more points, commonly about the Centre; Nature is also very cautious in Ossify­ing long Bones all at once; for if their Extremities had been Ossified as soon as their middle, the ligamentous and tendorous threads would not en­ter [Page 7] so easily their ends, to join them together, which they can do, being not totally Ossified. The Ossification, as I said afore of the Ossa Innominata, begins at three points, that they may have the greater solidity; but quite contrary in the Bones of the Cranium, for while the middle of most Bones of the Cranium are fully Ossified, their edges are only Membranous, that they may give way somewhat in time of Birth, which they would not, were the Cranium compleatly Ossified. These are the Reasons why Nature re­tards Ossification in some Bones, and advances it in others.

The Bones before they be through­ly indurated, Vessels. have many Blood-ves­sels, which are obliterated, as soon as the Meduller Glands are large enough to separate the Oily Particles from the Arterial Blood, (which have a Proper­ty of keeping the Bones soft) then the Ossific Liquor which is emitted from the aforesaid Glands hardens them, and so presses the Parts closer toge­ther, and hinders the Blood from pas­sing and repassing as usual, when [Page 8] they were softer, their bony threads gave way, and being then not prest so close; which Vessels are also boni­fied by the Ossific Juice, having lost their first use; yet some few remain, which serve only the Meduller Glands, for their Nourishment, the Pulsation of Blood in them having strength e­nough to scatter the Fibrils of the Bones in that Part, and so makes pas­sages for themselves.

The Bones are nourished two ways, Nourish­ment two fold. the one in their beginning, that is, when they are only Membranous, and is quite different from the Nourish­ment they receive after their Perfecti­on; for now they are nourished as all other Membranes, When Mem­branous. with Blood imme­diately from the Arteries, so that if you then cut them, you'll find every thread bloody, which is not so when truly Ossified; for when the Bones have occasion of greater solidity, Na­ture then changes her way of Nou­rishment, When Bony. which is by a peculiar Li­quor of a Saline Tartarous Nature, prepared by the Meduller Glands, the more oily Particles being separated, [Page 9] and kept in them, Medulla Quid. which is that we call the Marrow; this Liquor; I say, insinuates its self all along the bony strings, and is visible in a Fractured Bone, it appearing at their Extremi­ties, and meeting together causes them to reunite, Callus Quid. which we call Callus; nay, we often find that the adjacent Parts are sometimes indurated by this Ossific Liquor, and the Limbs often grow Gouty, and has not its former nimble motion, the Callus growing too big; for if they were bloody Particles, which exuded forth of their bony threads, instead of generating a Callus, it would Impostumate, for all Blood shed out of its Vessels putrifies, this Liquor is of such an indurating Quali­ty, that if the Fibrils of the Bones be any ways broken, that it sheds it self in any great quantity, it will Ossifie the very Tendons; I have seen the Marrow it self turn'd bony.

The Bones have Nerves (is plain) although no Sense, Nerves, but no Sense. for when they come to the solid Substance of the Bone, they are prest so close, that the Animal Spirits cannot enter their Sub­stance, [Page 10] and so consequently can have no feeling, Acids soften the Bones. unless softned by Acids, which will cause them to have a dull Sense, as may be try'd by the use of Acids on the Teeth; which, as the a­cidity goes off, reassume their former hardness, and insensibility. Some­times the Blood acquires such an aci­dity which is apt to cause a Spina Ven­tosa, Cause of a Spina Ven­tosa. which is nothing else but a Ca­riosity of the Bones, proceeding from an Acid Blood coming to the Meduller Glands for the Nourishment of the Bones; also Acid Acrid Humours in an Ulcer may cause a Cariosity.

The Differences observed in the Bones, Differences Nine. may be derived from Nine Things, viz. from their Substance, Quantity, Figure, Situation, Uses, Motion, Sensibility, Generation, and Cavities.

1 The First Difference is derived from their Substance, From their Substance. for some Bones have a very hard one, as the Tibia; others less hard, as the Vertebrae; and finally, others have a more soft and spongy one, as the Sternon.

[Page 11] The Second is derived from their 2 Quantity, From their Quantity. for some as those of the Thigh, Leg, Arm, &c. others less, as those of the Head; some least of all, as those of the Fin­gers.

The Third proceeds from their Fi­gure; 3 some are long, From their Figure. as the Os Femo­ris, Tibia, &c. others short, as those of the Fingers, and Metatarsus, &c. some round, as the Rotula; others flat, as the Ossa Palati; others square, as the Ossa Parietaria; others trian­gular, as the first Bone of the Sternon, Scapula, &c.

The Fourth is from their Situation, 4 From their Situation. as some are plac'd in the Head, others in the Trunk, and some in the Extre­mities; others are seated deeply, as the Officles in the Cavity of the Ear, &c.

The Fifth is from their Use, From their Vse. as some 5 serve to sustain the Body, as those of Legs and Thighs, others to contain and defend the Parts, as the Ribs de­fend the Lungs, Heart, &c. Ossa Inno­minata, and Os Sacrum, the Bladder, Womb in Women, &c. Cranium the Brain.

[Page 12] 6 The Sixth is known by their Moti­on; From their Motion. for some have a more manifest motion, as the great Bones of the Ex­tremities; others have a less, as those of Tarsus and Carpus; others none at all, as those of the Head.

7 The Seventh is from their Sense, From their Sense. which is easily remarkt, for all the Bones, generally speaking, have no Sense, except the Teeth, and they only a very dull Sense; except, as I have already observed, they be soft­ned by some offending Acid.

8 The Eighth is taken from the time of their perfect Generation, From the time of their Gene­ration. and Per­fection; for some Bones are perfect in the Womb, or before the Birth, as the small Officles of the Ears; and o­thers, which do not acquire their Per­fection, but as the Subject advances in Age, as all the rest of the Bones of the Body, yet some of these Ossifie quicker, as those of the lower Jaw; others slower, as the Fontanella of the Head.

9 The Ninth and last Difference is drawn from their Cavities, From their Cavities. for some have great ones, and contain Marrow, [Page 13] as the Bones of the Extremities; and there be others which have no mani­fest Cavity, but only Porosities; which contain a Meduller Juice, as those of Tarsus, Carpus, &c. some have holes, by which Vessels pass and repass, as those in the Basis of the Cranium and Vertebrae; others have only Trenches or Furrows, as those of the Sternon, Ribs; others have Si­nesses, as the Os Frontis, and Ossa Pe­trosa; lastly, some are pierced like the holes in a Seive, as the Os Cibri­forme.

The things to be consider'd in the Doctrine of each Bone are three; Threetian's consider'd in the Bones. 1. The Apophisis. 2. Epiphisis. And 3. Cavities, Furrows, and Sinusses.

First, Apophysis, of Process. The Bones not being of one 1 even Form, or Figure, have at their Extremities several Prominencies, or Protuberancies, which are of two sorts, the one is a continued part of the Bone jetting manifestly out, above its superficies, ordain'd for the more commodious and strong insertion of [Page 14] the Tendons of the Muscles, and is call'd an Apophysis, or Process.

2 The Second is an additional Bone growing to another by immediate contiguity, Epiphysis, or Apendage. as if Nature had forgot to make the Bone long enough, and is generally more porous than the Bone it self; which will separate if you boil in Oil, for they will not separate if boil'd in Water never so long, un­less the Subject be very young, it's call'd an Apendage, or Epiphisis; this in young Bodies may sometimes by great force be separated from the rest of the Bone, or to speak impro­perly, Dislocated.

If this Protuberance be round, it's call'd Caput, under which is the Cer­vix, as in the superior part of the Os Femoris; if it be flat, Cordilus; if sharp, Corone; others from their fi­gure are call'd Styloides, Mostoides, Coracoides, Ancyroides, &c.

Embrions have not these Protube­rances so large; for except some very few large ones, they are hardly vi­sible.

[Page 15] These Protuberances are either Na­tural, as the Spina of the Scapula; the rest are only Accidental.

The Accidental Protuberances of the Bones, Cause of the Protuberan­ces. (which are only manifest when the Bones are perfect) are cau­sed by the Tendons of the Muscles or Ligaments, which always are inser­ted there; for the stringy Filaments of the Tendons and Ligaments, en­tring into the Bones (while soft) between their stringy threads, cause them to inlarge there into a bulk, which it must do of necessity, there being a double portion of Fibres uni­ted together; which are all Ossified as the bony Liquor increases.

It's a general Note, that where you find such Protuberances, some Liga­ments or Tendons of Muscles are in­serted there; although these Protube­rances seem only to be accidental, Vses of the Protuberan­ces. yet they have many uses; first, by them the Muscles have a greater force to lift or pull up the Part. Secondly, they are of use to inlarge the Extremi­ties of the Bones, that the Body be sustain'd.

[Page 16] 3 The next part of the Bones, Cavities of three sorts. that come under our Consideration, are the Cavities, which are either Exter­nal or Internal: These Cavities are of three sorts, Holes, or Foramina; Trenches, or Furrows, and Sinusses.

1 A Foramina, Foramina, or holes. or Hole, is a Cavity which is perforated in a Bone, or made up of two Bones join'd together, as may be seen in the Basis of the Cra­nium, lower Jaw, Vertebrae of the Ribs. They are design'd for the pas­sage of the Vessels and Nerves, which pass through them, also the great Cavity of the Ischium may be call'd a Hole.

2 A Trench, Trenches, or Furrows. or Furrow, is not a Ca­vity through the Bone, but only a deep hole, or hollowness, long, or round, as the orbit of the Eye, &c. sometimes very shallow, as those in the inside of the Cranium, &c. some of a mean between both, as those in the Joints, to receive the Protube. rances of other Bones; some call these Sinusses, but improperly.

3 A Sinus is a sort of Cavity in a Bone, Sinusses. whereof the Orifice or Entrance is ve­ry [Page 17] strait, and the bottom large, such are in the Frontal Bone, &c.

I shall declare the use of all these Cavities, when I Treat of each Bone in particular.

All the long Bones of the Body are hollow in the inside towards the mid­dle, All long Bones hol­low. and contain a Marrow, which is only a heap of Membranous Vesicule, full of a fatty or oily Substance, call'd Meduller Glands; which, Meduller Glands. as I obser­ved before, separated the more oily Particles from the Blood, so that the more salfish only remain'd, which has the Ossific Virtue of rendering the Bones hard: The Ends or Extremities are porous, somewhat like a Pumice Stone, containing a Meduller Juice, Meduller Juice. like thin Oil, and have very few Glands; it's probable that the Liga­mentous strings entring the top of the Bones, divide and scatter the bony threads, which make it so porous.

The External Superficies of all Bones have a certain solid Cortex. Solid Cor­tex in all Bones.

All the External Cavities which serve for Articulation, have at their Circumference an Eminence call'd a [Page 18] Lip, to which is fastned a Circular Ligament, which embracing the Head of the received Bone, fortifies the Ar­ticulation.

As for each particular Process and Cavity, we shall describe them in the Demonstrations of each particular Bone.

Before I mention the Articulation of the Bones, I think it convenient to observe these things.

First, The Bones not of the same big­ness in Wo­men as in Men. All the Bones are not of the same greatness, and that not only in Persons of different Stature, but also in those of an equal Height, or Sta­ture; for some of these have their Bones smaller than others, and it's Beauty consists (as some have said it does) in the delicateness and small­ness of the Bones, then Women have all the Reason imaginable to have a better Shape and Symetry than Men, by reason their Bones are smaller; the Bones also of their Face are finer and more smooth.

There's also a great difference be­tween the Bones of the Ossa Innomina­ta, Difference of the Ossa in­nominata. [Page 19] which makes the Pelvis. In Men they are less and more unequal, but in Women larger, and smoother, to have a greater space to contain the Womb; also a Woman's Os Sacrum inclines more backwards than a Man's which makes their Buttocks more large.

We must also observe a difference in the Bones, Difference of the Bones according to Age. according as we grow in Years; for from the Birth to the twen­tieth Year, or thereabouts, the Bones continually increase, and from that to the sixtieth they continue in the same stay, neither increasing or diminish­ing; but after that they daily dimi­nish, by reason of the bony Fibres dry­ing, approach nearer one another, and so must consequently have a less bulk.

The Colour of the Bones is not a­like in all; Difference from the Colour. for some have them very white, others less, but some almost greyish; so that if you take the same Pains in whitening two or three Ske­letons, yet one will be doubtless whi­ter than the other.

[Page 20] It's true, Periostion. as I have observed before, that the Bones have no sense; yet they are Invested with a very sensible Membrane, call'd Periostion, as if we should say a Membrane over or inversing the Bone, it's very thin; all Bones have this, except the Teeth. I think there's a great Question about its Use. Vse. Some affirm it's to convey bloody Vessels to the Bones; but its rather believed to be for the greater implantation of the Tendons of the Muscles; for when you separate the Periostion, the Muscle comes off with it.

I shall now proceed to the manner of the Articulation of the Bones; there's such Art in the Conjunctions of the Bones, Articulati­on of the Bones. that they have served as a pattern to many Artizans in their Curious Works; for they could find nothing in Nature more fit to copy by; and although there be so many vari­ous ways of Articulation, as almost Junctures, yet they are all necessary, otherwise Man could never move him­self every way so compleatly as he does.

[Page 21] The Bones join'd together have ei­ther motion, or none, the former is call'd Articulation, the latter Symphy­sis, Or growing together.

Articulation, Articulation twofold. is either for manifest, or obscure motion: The first is call'd Diarthrosis, or loose Articulation, the other Synarthrosis, or more close and compact.

Diarthrosis is Threefold, 1. Enar­throsis. 1. Diar­throsis threefold. 2. Anthrodiae. 3. Gyngli­mus.

1. Enarthrosis, Enarthro­sis. is when a large Head is received into a deep Cavity, as the Os Femoris in the Acetabulum of the Ossa Innominata.

2. Arthrodia, Arthrodia. is when the Cavity is shallow, and the Head of the re­ceived Bone also shallow and flattish, as the Os Humeri, with the Scapula, and the Bones of the Metacarp and Metatarse; with the first Phalanx of the Fingers and Toes.

Now the Bones which are Articu­lated by Enarthrosis, and Arthrodia, are capable of all sorts of motion, as upwards, downwards, forwards, [Page 22] backwards, and circularly; yet the deeper the Cavity, and the more bony the Edges are, the motion is render'd more slow, and not so brisk and nim­ble as when the Cup is not so deep; These two all sorts of motion. this is seen in the Os Femoris, and Ace­tabulum, for the Os Humeri being in­serted in a more shallow Cup, is ca­pable of all sorts of motion, and that to a great degree, yet about the Cup or the Scapula there are several Carti­lages, which make it seem as deep as the Acetabulum, but at the same time by giving way, hinders not the very free motion of the Humerus.

Ginglimus, Ginglimus threefold. is when the same Bone both receives, and is received, and is Threefold. 1. Ginglimus Proximus. 2. Longus. 3. Compositus.

1. Ginglimus Proximus, Proximus. is when a Bone is received by another, and re­ceives the same, as the lower part of the Os Humeri, and Ʋlna.

2. Ginglimus Longus, is when two Bones are join'd together according to their length, Longus. so that the one Bone ha­ving a Cavity in its side towards the [Page 23] end, receives the head of the other, which has a Cavity likewise at its o­ther Extremity, to receive a Protube­rance of the first Bone, as the Radius and Ulna.

2. Ginglimus Compositus, Composi­tus. is when a Bone receives one, and is received by another, as in some of the Vertebrae of the Back, where one receives the up­per, and is received by the lower: Ginglimus Compositus, is also when a long Process of a Bone is inserted into another above it, and so turns in the Cavity as an Axis in a Wheel, as the second Vertebra of the Neck with the first.

As Enarthrosis, and Arthrodia, Ginglimus for Flexion and Exten­sion ouly. serve for all sorts of motion, Ginglimus serves only for Flexion, and Extensi­on; yet in the Radius and Vlna it serves for Pronation and Supination.

When a Bone is join'd by double Arthrodia, it makes a sort of Gingli­mus, as may be seen in the lower Jaw.

Synarthrosis, Synarthro­sis. or obscure motion, is in the Ribs which have a little motion in their ends towards the Vertebrae in [Page 24] Respiration; also most of the Bones of the Tarsus and Carpus, which in great pressure give way a little, for the more easie motion of the Part.

Symphysis, 2. Symphy­sis Three­fold. is only when the Bones are united without any motion at all, and is Threefold, as Sutura, Harmonia, and Gomphosis.

1. Sutura, Sutura. is when the Bones are united together in their edges by little Points, or Teeth (as it were) un­equally, as may be seen in the Bones of the Cranium.

2. Harmonia, Harmonia. is an union of the Bones by a simple Line only, either streight or curved, as the Bones of the Nose, Face, Palate; but this is only in their outward part, for we always find them Internally Serratil, or Su­ture like.

3. Gomphosis, Gompho­sis. is when one Bone is fastned in another, as a Nail in Wood, so are the Teeth in the Jaws.

Some add to the symphysis several other sorts of Articulations, as Syn­chondrosis, Syssarcosis, syneurosis, vel Syntenosis.

[Page 25] Synchondrosis, Synchon­drosis. is when a Cartilagi­nous Substance interveens, as may be seen in the middle of the lower Jaw; which in young are two distinct Bones, but as the Ossific Liquor pre­dominates, grow one; also the Ossa Pubis are united by it, so are the Bo­dies of the Vertebrae one to another.

Syssarcosis, Syssarcosis. is when a Bone is fastned by Means of Flesh only, as the Os Hy­oides in the Mouth, and the Scapula to the Ribs.

Syneurosis, Syneurosis. vel Syntenosis, is when Bones are united together by means of Ligamentous Parts, as the Rotula with the Bones of the Legs; but I think these are not properly Articula­tions.

The Bones of the Body in an Adult, Number 245. are accounted 245. For Example, the Head has 64, the Trunk 57, the Arms and Hands 64, the Legs, &c. 60, which makes in all 243. Some per­haps may wonder why the Great Crea­tor composed such a number of Bones; I Answer, how could the Hand or Arm perform all the Actions it does, and put it self in so many Thousand [Page 26] Postures, had it not many Junctures and Articulations? For had the Part been compos'd but of one or two Bones, how Lame and Preposterously would it have acted? The same may be said of the Legs, &c. And if the Spine had not been made up of such a number of Vertebrae, how could we have bent, or mov'd it as we do? It was therefore convenient and necessa­ry for the Perfection of Man and his Functions, to have as many Bones as he has.

The Head, Head 64. as I said, is made up of 64 Bones, which are thus number'd, 6 proper of the Skull, 8 of the Ears, 4 in each, 3 Common of the Skull; Face 11, with the Vomer; Os Hyoid 1, lower Jaw 1, though some make it 2, Teeth about 32, which make 62; but if you add the Ossa Spongiosa, they make 64.

The Trunk consists of 57 Bones; Trunk 57. Vertebrae 25, as 7 of the Neck, 12 of the Back, 5 in the Loins, and 1 in the Os Sacrum, which some say is made up of 5; 3 in the Coccyx, Ribs 24, Sternon 3, Ossa Innominata 2, which

• [Page]The Bones of the Body are those; of the
  • Head,
    • Whose Parts are ei­ther of the Cra­nium, which has,
      • Proper Bones 6, as,
        • Os Frontis 1.
        • Ossa Sincipitis 2.
        • Occipitis 1.
        • Temporum 2.
          • In whose Foramina Auditoria are 8 Bones, 4 in each
            • Malleus.
            • Stapes.
            • Incus.
            • Os Orbiculare.
      • Common Bones 3▪
        • Os Sphenoides.
        • Os Cribriforme.
        • Os Jugale.
          • To which is annex'd; Ossa Spongiosa 2.
      • Of the Bones of the Face,
        • In the Superior part are 11 Bones; 5 pair and an odd one, Upper Jaw.
          • Ossa Triangularia.
          • Ossa Lachrimalia.
          • Ossa Malae.
          • Ossa Nasi.
          • Ossa Palati.
          • Os Vomer.
        • Lower Jaw 1.
          • Teeth in both Jaws 32.
            • Incisorii 8.
            • Canini 4.
            • Molares 20.
    • To which is Annexed, the Os Hyoides, join'd by Syssarcosim.
  • Spine, in which are the Bones of the
    • Neck, in which are 7 Vertebrae.
    • Breast, divided in­to the
      • Fore-part, in which are,
        • Clavicles 2.
        • Ossa Pectoris 3.
      • Lateral-part, in Which are,
        • Ribs 24.
      • Back-part, in which are,
        • Scapulae 2.
        • Vertebrae 12.
    • Loins, divided in­to the
      • Fore-part, in which are,
        • Ossa Pubis 2.
      • Lateral-part, in which are,
        • Ossa Ilia 2.
        • Ossa Coxendicis 2.
          • These join'd toge­ther in Adults, make up the Ossa Innominata.
      • Back-part, in which are,
        • Lumborum Vertebrae 5.
        • Os Sacrum, which some make 5.
        • Ossa Coccygis 3.
    • Limbs, which are either,
      • Superior, or Hands, divided into
        • Os Humeri 2.
        • Cubitus ejus
          • Radius
          • Vlna
        • Lower-part, or Hand, strictly so called, whose Parts are,
          • The Wrist 8.
          • Metacarpus 4.
          • Fingers 15.
            • Three in each.
          • To which are annex'd, some Ossa Sesamoidea.
      • Inferior, or Feet, divided into
        • Bones of the
          • Thigh
          • Patella
        • Leg, strictly so call'd,
          • Tibia
          • Fibula
        • Lower-part, or Foot, strictly so call'd in which is
          • Tarsus, Bones 7.
          • Metatarsus 5.
          • Fingers or Toes 14.
          • To which are annex'd, Ossa Sesamoidea.

[Page] [Page] [Page 27] makes up the number of 57.—I once saw a Skeleton which had 13 Ribs on each side.

The upper Extremities, or Limbs, consist of 64 Bones, Vpper Limbs 64. taking in the Cla­viculae, which I think we ought to do, since much of the motion of the Arms depends on them; there's 32 Bones in each Arm then, as Clavicula, Scapula, Os Humerus, Radius, and Vlna; 8 Bones of the Carpus, 4 of the Metacarp; and Bones of the Fingers 15, 3 in each, accounting the Thumb as one Finger, which added to the other Arm makes 64.

The Lower Extremities consists of 60, Lower Limbs 60. that is, 30 in each; as the Os Femoris, Rotula, Tibia, and Fibula; 7 in the Tarsus, 5 in the Metatarsus, and 14 in the Toes, which makes to­gether with the other Leg 60.

Some augment the number, who make many of the Os Hyoides, 3 of the Os Innominatum, 2 of the lower Jaw, 5 of the Os Sacrum, and add the Ossa Sesamoidea, which are not often found, and then for the most part in the great Toes, which would then make up a­bove 250.

[Page 28] I am come now to the last Conside­ration of the Bones in General, Vse of the Bones. which is their Use.

They have many Uses; 1. They serve for the support of the Body, be­ing as so many Beams or Pillars in a House. 2. For the Defence of some Noble Part, as the Skull for the Brain, Ribs for the Heart, Lungs, &c. Ossa Innominata and Sacrum, which make the Pelvis for the Womb, Bladder, &c. 3. For the Progression and Motion of the Animal, of which with the Mus­cles, they are the only Instruments. 4. To give Shape and Figure to the whole Body; these are the General Uses, as for their Particular, we shall speak of them in the Demonstration of each particular Part.

Demonstration II.
Of the Bones of the Skull.

WE now come to the Doctrine of the Bones in particular; Skeleton di­vided into three parts. we di­vide the Skeleton into three parts, as the Head, Trunk and Limbs.

By the Head we understand not on­ly all the Bones of the Skull, but also those of the Face, even from the Ver­tix to the first Vertebra of the Neck; by the Trunk all that composes the Neck, Back, Loins, Os Sacrum, Ossa Innominata, Sternon, &c. By the Limbs those which make up the Arms and Legs, generally so called; of all which in order. The Head is subdi­vided into the Skull, properly so cal­led, and the Face.

The Skull (I mean that upper part whose Bones compose, Figure of the Skull. and make up a large Cavity, which contains the Brain, in which you must consider its Figure altogether) is globous, some­what [Page 30] what long, but flattish towards the sides, for the better Situation of the Temporal Muscles; which being on, make it look more round.

All the Bones of the Skull are made up of two Laminae or Plates, Skull, two Tables. call'd Tables, one Internal, the other Ex­ternal, between which lyes a Medul­lar Juice, of a reddish Colour, call'd the Pith, Diploe, what. or Diploe, which is very discernable in young Persons; but as we grow in Years, the Ossific Liquor invading, it bonifies.

The Exterior and Superior Superfi­cies of the Cranium; is very smooth, and polished, having few inequalities; but where the Sutures are, the Inter­nal Superior Superficies is not so equal, having many little Sulci, or Furrows, which are caused by the Vessels of the Dura Mater, when the Skull is but Membranous, being then capable of receiving any Impression, that the Pulsation of the Vessels give it, Cause of the Furrows. so make themselves Furrows; but its Internal Inferior Part is very unequal, by reason of the many Productions and Cavities found there.

[Page 31] The Cranium has many Foramina, Foramina in General. which give way or passage to the Ves­sels sels passing and repassing, which fill up these holes so close, that no Fumes or Vapours, as the Antients believed, can get in, or come forth, unless by the Vessels themselves: we will shew all these holes, at the latter end of this Demonstration.

It's a Question, The bigness of the Cra­nium, de­pends on the Brain. whether it be the Cranium, which gives greatness to the Brain; or whether the Brain gives form to the Cranium, I Answer, that the bigness of the Cranium depends on that of the Brain, for two Reasons; First, the Cranium, while Membra­nous, especially towards the Sutures, extends it self more or less, as the Brain increases: The Second, is that the Cranium is not totally Ossified till the Brain is arrived to its full Magnitude; for we see in an Infant new-born, that although the Brain be perfect, yet at the same time, the Cranium is only Cartilaginous about the Sutures; though bony in the middle of every Bone, nay, the Fontanella does not Os­sifie under some Years; from whence [Page 32] also it is, that in Labour these Bones, as I have before observed, give way, and fold over one another, for the more easie exit of the Infant out of the Womb.

The Bones of the Cranium are join'd together by Sutures, Sutures, twofold. which are of two sorts, true, or false; or to speak more properly, common, or proper.

The Proper are Eight. Proper, three.

1 1. Coronalis, Coronalis. ( vel Frontalis) because the Antients used to wear their Gar­lands on that part of the Head, it reaches from one Temporal Bone to the other, joining the Os Frontis to the Ossa Parietaria.

2 2. Lambdoides being like the Greek Letter [...], Lambdoi­des. others call it Triangularis; this Suture is seldom wanting, what­ever the rest are; it begins at the Basis of the Os Occipitis, and ascends ob­liquely to the middle of the back-part of the Head, and descends again to the other side of the Head; the Point in the middle is call'd Vertix, Vertix, what. by rea­son the Hair on the Scalp commonly turns there; it joins the Occipital Bone [Page 33] to the Bones of the Temples, and Ossa Parietaria.

3. Sagittalis, Sagittalis. because it runs length­ways 3 as an Arrow; it begins at the Vertix of the Sutura Lambdoides, and marching strait forwards to the mid­dle of the Coronal Suture; in Chil­dren it divides the Coronal Bone, and goes quite to the Nose, which as we grow in Years vanishes; yet I have seen it in the Cranium of some A­dults.

The Sutures being so united toge­ther, make up a Figure almost like this )—<.

Some of our Modern Anatomical Professors, will have the Sutures to be Serratil only in the Superior Ta­ble, but join'd by Harmony in the Lower, but it's always found to the contrary.

The Common are Five, Common, five. or more; these are the Chief, 1. The Suture Squamose, Squamosae. or Scale-like, because ap­ply'd as one Scale on another; they are two, one on each side, which a­rise from the outside of the Mastoid­process, and circumscribing the Tem­ple-bones, [Page 34] descend Circularly to­wards the Basis of the Ears.

Whatever Anatomists say, I think them true Sutures, being Serratil as well Internally, as Externally.

2. Orbalis, Orbalis. it begins at the top of the Sutura Squamosa, and descending obliquely towards the Orbit of the Eye, crosses on the top of the Nose, so passes over the other Eye, and so on to the other Squamous Suture.

3. Nasalis, Nasalis. which divides the Bones of the Nose.

4. Sutura Basilaris, Basilaris. which separates the other Bones from the Os Basilare.

5. Sutura Ethmoides, Ethmoides seu Cribrifor­mis, dividing this Bone from the Os Frontis; some say that these Four last are rather Harmonia, than Sutura, but Demonstration shews the contrary.

The Sutures have many uses, Vse of the Sutures. the principal are these; 1. Many Liga­mentous Fibres pass through them from the Dura Mater to the Pericrani­um, which suspends the Dura Mater, so are a sort of hinderance of too vio­lent Concussions of the Brain, in any great motions of the Body; for by [Page 35] these Fibres the Brain is kept more light; it's by this Communication, that when the Pericranium is wound­ed, an Inflammation often arises in the Dura, Mater, as if it had received some offence it self: These Fibres also, by suspending the Dura Mater, and keeping it close to the Interior Surface of the Cranium, the Arteries in the Cortical part have a freer motion, which would be somewhat impeded, if it fell on the Brain. 2. They give passage to several Vessels, that are pas­sing and repassing to the Diploe, for the Nourishment of the Bones of the Cra­nium. 3. They are of use in hinder­ing Fractures from passing further than one Bone, for they always stop at the Sutures, which if the Skull were but one continued Bone, the Fracture would be apt to run over all the Cra­nium, as may be seen daily in any Earthen or Glass Vessel, when crackt by a stroke, it commonly runs almost quite over, or round. Some say, a fourth Use is, to give a vent or breath­ing to many Fuliginous Vapours ga­ther'd within the Cranium, but I much [Page 36] question this use; yet some say, that many who have had their Sutures too close, have been subject to insuppor­table Head-aches, Transpiration ha­ving been stopt, as they say; but I rather think it proceeded from the pressure of the Vessels which pass through them, which causing an Ob­struction of the flowing Liquors, was a cause of these Pains.

There are many Observations in se­veral Authentick and Learned Au­thors, Some have had no Su­tures. of some who have had none, or very few Sutures, and others who have had more than usual. I saw a Skull lately in the Hands of an Ingeni­ous Chirurgeon, my very good Friend, which had a Suture running transverse the Occipital Bone, and the Sagittal pass'd quite through the Os Frontis, and it was the Skull of an A­dult; such is the various Disports of Nature; also in very Old Age the Su­tures are almost obliterated, the Ossi­fic Liquor then predominating.

Embryons have no Sutures, How the Sutures are made. or at least not to be well distinguished, their Skulls being wholly Membranous; so [Page 37] while the Ossific Liquor, (which as I have said, begins at a point, &c. in the Cranium) insinuates it self along the bony Threads, and by degrees har­dens them, some Fibrous and Vascu­lar Strings passing from the Dura Ma­ter to the Pericranium, hinders in those places the bony Liquor from u­niting, so forms these Seams or Su­tures; for in a Foetus the Skull being as yet Membranous in its edges, wrap, or fold themselves as it were one over another, to take up less room in the Birth; for had the Skull been totally Ossified before the Birth, the Infant would for the most part endanger the Life of the Mother; this may be daily seen in young Children, where the Skull is wholly Membranous in the top of the Head between the Coronal and Sagittal Sutures, which place is call'd Fontanella. Fontanel­la, what.

The Bones of the Skull are either Proper or Common; the Proper are Six in number.

1. The Os Frontis, Proper Bones of the Skull, Six. or Coronalis, the Forechead-Bone; of a Semicircular Fi­gure, [Page 38] in its superior part, situated in the Superior part of the Face, and An­terior of the Cranium, bounded above by the Coronal Suture from the Ossa Parietaria, on the sides by the Ossa Temporum, below by the Transver­salis, or Orbalis from the Nose, Eyes, &c.

The things to be consider'd in this Bone, are its Cavities and Processes.

Its outside is smooth, as are most of the Bones of the Cranium, no Tendons or Ligaments being inserted here.

The Ossification begins in this Bone at two Points, between the Laminae of this Bone there's a Cavity call'd Sinus Frontalis; 1. Os Fron­tis. it's oft-times double, which by two small Foramina enter into the Nostrils; this Sinus makes the inside of this Bone arise in a ridge, which be­gins about the top of the Forehead, where the Hair grows not, and reaches to the Crista Galli; ☜ for which reason we must not Trepan here, lest we of­fend the Dura Mater on each side the ridge, whenas the middle is not per­forated by much; the upper Lamina of this coming to the Eyes, where [Page 39] turning inwards, makes up part of the Orbit on the upper side: This: Sinus is lined with a thick Membrane full of Glands, which separate a Mucus to moisten the Nose; in Brutes it's very large, but not so in Men; yet once I saw a Skull which had it extreamly large, and divided in four or five Cells, quite round the Basis of the Os Frontis, so that the Internal Protu­berances almost hid the Crista Galli; ☞ yet sometimes this Sinus is quite obli­terated, and the Membrane turn'd bony, as the Ossific Liquor increases, and we incline in Age.

In its lower part over each Eye is a small Foramen, Foramine. through which passes a Branch of the five pair of Nerves to the Musculous Flesh on the Forehead.

It has Four Processes; Processes. the two grea­ter at the Internal Canthus of the Eyes, the other two at the less; its inner Lamen about the Eye-brows towards the Nose, bunches inwards, so causes a hollowness there, which is part of the Sinus Frontalis.

2. The Os Occipitis is opposite to the Coronal, 2. Os Occi­pitis. in the hinder part of the [Page 40] Head, it's the thickest and strongest Bone of the Head; the reason whereof is this, we having no Eyes behind, Nature has framed it of a thicker con­sistence, to the end it may the better resist any stroak or blow it receives; it's five-corner'd, join'd to the Ossa Parietaria by the Lambdoid Suture, and to the Ossa Temporum by the Squamous Sutures, and it's bottom to the Os Sphenoides, by a sort of Har­mony.

The things to be consider'd in this Bone, are its Sinusses, Foramina, and Processes.

Its Sinusses, Sinusses, or Sulci. or rather Sulci, are many, two on the External part just behind the Foramen Medullare; and seven in the Internal Superficies, the two largest of which contain the Pro­tuberances of the Carebel, the other are of small moment.

It has five Foramina or Holes, Foramina. the lowest and largest call'd Foramen Me­dullare, the Spinal Marrow passing by this hole to all the Vertebrae; the other four are less, and only serve for the exit of the Vessels; two give passage [Page 41] to the Nerves of the Tongue, and two to the Arteriae Cervicales; these are proper Foramina, there are two others which are common both to it and the other Bones, one on each side the Os Petrosum, which give passage to the eighth pair of Nerves call'd parvagum, and to the two Internal Jugular Veins.

It has five Processes, four of which are on the outside by the Foramen Me­dullare; the two innermost are call'd Condyli, Processes. and are received by the two shallow Sinus's of the first Vertebra of the Neck, serving for the Articulati­on of the Head; in its Internal part it has a long Protuberance or Ridge, which ascends in the middle from the Foramen Medullare, and parts the Pro­tuberances of the Cerebellum, this is its fifth Process.

There's another small Protuberance or Process, A sixth Pro­cess, not de­scrib'd by a­ny Author. which is not describ'd by any Author; it lyes between the Condyli, from it passes a Ligament, which joins it to the first Vertebra of the Neck.

[Page 42] It has also several small Prominen­ces towards its Basis on the outside, some Tendons being inserted there.

Third and fourth are the Ossa Sinci­pitis, vel Parietaria, Third and fourth, Ossa Sincipitis. because alike, or forming the Walls of the Cranium, as it were; they are the thinnest Bones of the Head, are join'd by the Coro­nal Suture to the Os Frontis, to the Occiput by the Lambdoidal, to the Ossa Temporum by the Squamosae, and to one another by the Sagittalis: They are very smooth on their outside, but somewhat unequal within, Sulci. having many small Sulci, or Furrows, for the reception of the Vessels of the Dura Mater; they are thinnest towards the Sutures, as are all Bones of the Crani­um; these Furrows are thus caus'd, How caus'd. while the Skull is Membranous, the Vessels by their Pulsation make them­selves these Furrows.

These Bones are of a Quadran­gular Figure. Figure.

Anatomists call that the Bregma of the Head, Bregma, what. where these two Bones are united together by the Sagittal Suture, towards the Coronal Bone.

[Page 43] The fifth and sixth Bones are call'd Ossa Temporum, Fifth and sixth, Ossa Tempo­rum. so call'd a Temporibus, because as a Man grows old, the Hairs on the Temples whiten the soon­est; they lye on the sides of the Skull, being join'd above by the Squamous Sutures to the Ossa Parietaria, before to the Process of the first Bone of the upper Jaw, below to the Sphenoidal Bone, and behind to the Os Occipitis; their superior part is smooth, thin, and semicircular, so sometimes call'd Ossa Squamosa; Ossa Squa­mosa & Pe­trosa. Sinusses. their inferior thick, and hard, and call'd Ossa Petrosa.

Their Parts to be consider'd, are Si­nusses, Processes, and Holes.

These Bones have two Sinusses each; the first is large, and lin'd with a Cartilaginous Substance, plac'd be­tween she Meatus Auditorius, and its long Process, which makes up part of the Os Jugale, Glenoides. call'd Sinus Glenoides, and receives one of the Processes of the lower Jaw, call'd Condylus; the other two are less, and lye on the inside of the aforesaid long Process.

Each Bone has four Processes, Processes. three External, and one Internal.

[Page 44] The First is call'd Styloides, Styloides. being slender, sharp, and long; some take it to be an Appendix only; in Infants it's Cartilaginous; those Animals which want these Processes, ☜ their Os Hyoides have a double Horn, or Pro­cess which supplies its place, many Muscles arise from it.

Secondly, Mastoides. Mastoideus, or Mamilla­ris, because like a Cow's Teat; 'tis blunt, thick, and short, hollow with­in, plac'd at the botton of the Audi­tory passage.

Thirdly, Jugalis. Processus Jugalis vel Zygo­maticus, very long, somewhat broad, and curved, it's thin, arising a little from the outside of the Sinus Glenoides, and meeting with another long Pro­cess belonging to the first Bone of the Maxilla superior, are join'd together by an oblique Suture, and make up the Os Jugale, or Bridge.

Fourthly, The Internal Protube­rance is call'd Petrosus, Petrosus. from its hard­ness, or Auditorius; it's somewhat long, and jets out towards the inner Basis of the Skull, or Os Sphenoides; it's hollow, and contains the Instru­ments [Page 45] of Hearing: Four small Bones of the Ear. It has four little Bones within its Cavity.

1. Incus, or the Anvil.

2. Malleus, the Hammer.

3. Stapes, the Stirrup.

4. Os Orbiculare, which lyes just on the top of the Stapes.

These Bones are as big and perfect at the Birth, as in Adults; they are Articulated after this manner, Manner of Connexion. the A­pophisis of the Malleus is fastned to the Tympanum, and Articulated by its Head in the Cavity of the Incus; this Incus has two Feet, the shortest of which is plac'd on the Tympanum, and the longer on the Stapes, on which lyes the Os Orbiculare.

These Bones have many Foramina each. Foramina.

The First is External, and call'd Foramen Auditorium, seu Meatus Audi­torius, Meatus Auditori­us. by which the Sound enters to the Organs of Hearing.

Its Second, Is narrow, short, and oblique, by which the Jugular Vein enters the inner Cavity of this passage.

[Page 46] The Third, Is between the Styloid and Mastoid Process, and ends in that which goes from the Ear to the Mouth.

The common Bones are three. Common Bones, three.

1. Os Sphenoides, Os Sphe­noides. Basilare, vel Cu­neiforme, some call it Polyforme, from its strange Figure; it's not call'd Cu­neiforme, as if it were like a Wedge, but by reason it's seated between the Bones of the Skull and upper Jaw; in Infants it consists of two or three Bones; it's very thick at its Basis, but thin towards the Temples. It's join'd to, or touches all the Bones almost of the Cranium, and some of the Bones of the upper Jaw, to which it's fastned by the Sphenoid Suture.

Its Parts to be consider'd, are either Processes, Sinusses, or Foramina.

It has eight Processes, Processes. four Inter­nal, and four External.

The Internal are call'd Clinoides, Clinoides. they resembling the Feet of a Bed; these with the deprest Sinus in the middle, Sella Tur­cica. make up the Sella Turcica, be­ing like the Seat of a War-saddle, on [Page 47] which lyes the Glandula Pituita­ria.

Two of the External are call'd Pte­rigoidei, Pterigoi­dei. seu Aliformes, or the Bats Wings, being like the Wings of a Bat; the other two have no Name.

The Sinusses are many. Sinusses. It has one in each Process, call'd Pteregoides, Pteregoi­des. to give way to the Musculi Pteregoidei Interni: It has also a very large one in the middle of the Sella Turcica, to re­ceive the Glandula Pituitaria.

Within this Bone lyes a true Sinus, Basilaris. call'd Basilaris, which have the same Glands, and separate the same Juice, as the Sinus Frontalis, and has the same use.

The Foramina, Foramina. are either Common, or Proper.

The Common are those which lye between it and the Ossa Petrosa, through which the Jugulars pass; the proper are twelve, six on each side; the first pair is call'd Transcolatores, Transcola­tores. which serve as a discharge to the Glan­dula Pituitaria; the second Foramina Optica, Optica. by which passes the Optick Nerves; the third Motoria, Motoria. by which [Page 48] passes the Motory Nerves; the fourth call'd Crotophites; Croto­phites. the fifth Gustatoria, Gustatoria. by which the Tasting Nerves pass; the sixth call'd Carotides, Carotides. by which the Carotid Arteries pass.

The second Common Bone is call'd Os Cribriforme, Os Cribri­forme. being perforated like a Seive, the Fibrils of the Olfactory Nerves pass through these Holes; it's seated at the middle of the Basis of the Forehead, to which it's join'd by Har­monia; it's also join'd to the two Bones of the upper Jaw, and behind to the Os Sphenoides.

On its inside it has an almost Trian­gular Process, call'd Crista Galli Crista Gal­li. the Coxcomb; it arises just where the Process of the Sinus Frontalis ends, and reaches about half way in the middle of the Bone; the Falx which divides the two Lobes of the Brain, is tyed to the point of this Process.

On its outside, Septum Nasi. just opposite to the Crista Galli; it has another very thin, but hard Process, call'd Septum Nasi, dividing the Nostrils.

[Page 49] To the Os Cribriforme is annex'd two other very fine and thin Bones, Ossa Spon­giosa. one in each Nostril, call'd Ossa Spongiosa, they be wrapt up, as it were, in many folds, and lin'd with a Membrane made up of the Expanded Fibres of the Ol­factory Nerves; ☞ so that those Crea­tures, who have more of these Lami­nae have a more exquisite smell, as Cats, Greyhounds, &c. for a Man has not above three or four folds, whereas the above-nam'd Creatures have very many; so that it's not dif­ficult to judge of the acuteness of the smell, from the multiplicity of these folds; most Anatomists consider them as parts of the Os Cribriforme, using the one for the other promiscuously; but I think them to be different Bones.

The third Common Bone is call'd Os Jugale, Os Jugale. vel Zygoma, by some the Bridge, or Yoak-bone; it's not one distinct Bone, but made up of a long Process of the Temporal Bone, and another of the first Bone of the upper Jaw.

[Page 50] It's situated on the outside of the Face, Situation. under the External Canthus of the Eye, there's one on each side.

Its use seems as if ordain'd by Na­ture, Vse. for the defence of the Temporal Muscle which passes under it; it also gives Origination to the Musculi Mas­seteres.

Demonstration III.
Of the Bones of the Face.

IF the structure of the Bones of the Cranium be worthy our Admirati­on, the Composition of the Bones of the Face, which now comes under our view, is no less surprizing; for al­though that contains the Brain, which is one of the most Noble Parts of the Body; yet the Face where most of the Senses are lodged, and for many Rea­sons may be call'd the Image of the Soul, since most, if not all the Passions of the Mind, are fully demonstrated in the Face, cannot merit less, especi­ally in the wonderful structure of the Bones which compose it. The Face is also the Seat of Beauty, which Charms and Attracts the Eyes of all to behold it; The Bones give Figure, Form, and Beauty to the whole Body. and nothing contributes more to this Beauty than a good For­mation, and true Symmetry of the Bones: Ex. gratia, if the lower part [Page 52] of the Coronal Bone bunch out too much, it makes them Beetle brow'd, as we call it: If the Bones of the Nose be too large, and rising from the Face, it makes them Hawk-nosed: If the lower Jaw be too sharp, or pointed, it makes an Out mouth, and so of the rest; yet we may say the same of the Bones of the whole Body, they giv­ing, as I have said, Shape and Figure to all; so that if they be any way de­form'd or unproportioned, that part must of necessity be disfigured.

The Bones of the Face are divided into those of the upper and lower Jaw. Division.

The Bones of the superior Jaw are eleven in number, Bones of the upper Jaw, eleven. five on each side, and an odd one.

The Ossa Triangulares are big, 1, 2, Ossa Trian­gulares. of a hard and solid Substance, in Figure triangular, wherefore so call'd, plac'd on the lower side of the outward Can­thus of the Eye's Orbit, the middle are advanced out, and rising, which forms the Balls of the Cheeks: One of their Angular Processes, as I said before, makes up the Os Jugale, being join'd [Page 53] with the long Process of the Temple-Bone; they also make the inferior part of the Orbit of the Eyes, and is united to four Bones, viz. the Coronalis, Sphenoides, Maxillary, and Os Petro­sum.

They have three Apophises each; Apophisis, three. one of which makes an eminence, which forms the lesser Angle of the Eye; the other advancing towards the Nose, makes the greatest part of the inferior Lip of the Orbit; the third may well be call'd Processus Jugalis, which I have already mentioned.

The Ossa Lachrimalia, 3, 4, Ossa La­chrimales. seu Ʋnguis, are very little and thin, in shape of a Nail of a Man's Hand, seated in the great Canthus of the Eyes, within the Orbit; there's a small Foramina, in each call'd Lachrimale, in which the Lachrimal Duct passes to the Nose, Puncta La­chrimalia. also through this hole passes a Branch of the fifth pair of Nerves, to the in­ner Membrane of the Nose.

These Bones are so small, that they be easily lost.

The Ossa Male 5, 6, Ossa Maxil­lares. some call them Maxillares, are the thickest, greatest, [Page 54] and spongiest of all the Bones of the Face, and makes up the greatest part of the Cheeks and Palate.

Parts to be consider'd in these Bones, are first, many deep Cavities which are in their lower edge, call'd Alveoli, Alveoli. or Sockets, in which the Teeth are fastned: Secondly, each has an Inter­nal Sinus, which is lin'd with the same sort of Glandulous Membrane, as the Sinus Frontalis, and of the same use, and is call'd Sinus Maxillare. Sinus Max­illare. There's also another long one, which runs a­long over the Roots of the Teeth, in which the Vessels pass which serve for the Nourishment of the Teeth.

The Ossa Nasi are two long, 7, 8, Ossa Nasi. hard, and somewhat thick Bones, of a Pyra­midal Figure each, being join'd, they make up the bony or superior part of the Nose; their lower Extrmities are somewhat unequal, for the more strong Connexion of the Cartilages of the Nose with it; they are join'd to­gether by Harmonia.

The last pair are call'd Ossa Palati, 9, 10, Ossa Palati. are very broad, but thin, and being join'd by Harmonia, make up the Roof [Page 55] of the Mouth; they are join'd to the Ossa Maxillares forwardly, and back­wardly, sideways to the Pterygoid A­pophisis, by the Sphenoidal Suture: Each Bone has a hole forwardly, call'd Foramen Gustativum.

The eleventh Bone of the upper Jaw is call'd Vomer, 11, Os Vomer. by reason the An­tients say it resembes a Plough-share; it's situated in the middle over the Palate, edgeways, and is, as it were, a sort of Septum, dividing the interior part of the Nostrils.

Before I pass to the lower Jaw, Orbita Oc­culorum. 'twill not be amiss to give a Descripti­on of the Orbits of the Eyes; they are two great Cavities plac'd at the infe­rior part of the Os Frontis, which serve as Habitations to the Eyes, and to defend them against all Injuries; their external part is quite round, but internally they grow Pyramidal, ha­ving at their bottom many perforati­ons for Vessels, &c.

Each Orbit is made up of part of six different Bones, Each Orbit made up of six Bones. which altogether composes its Cavity.

[Page 56] Five of which are Common, and one Proper, which is call'd, as I have already demonstrated, Os Vnguis vel Lachrimale: Of the Common, three belong to the Cranium, and two to the Face; the first of those of the Crani­um, is the Coronal, which forms the superior part; the second is the Eth­moidal Bone, which forms part of the internal side next the Nose; the third is the Sphenoidal, which makes up part of the internal Cavity; the two of the Face compose all its lower part, the Os Triangulare forming that part towards the lesser Canthus, and the Maxillare, that next the greater.

The lower Jaw is but one continu­ed Bone in Adults, Inferior Jaw. but in young Bodies is composed of two join'd together in the fore-part, by Syncondrosis; they u­nite, and become one about the se­venth Year, of a somewhat Circular Figure, or rather like the Greek Let­ter Ʋ, smooth and polished without, but a little rough within, several Muscles being inserted, and arising from thence.

[Page 57] This in all Creatures is only move­able, except as some affirm in the Cro­codile, who moves the upper only.

The Parts to be consider'd in this Bone, are its Processes, Foramina, and Alveoli.

It has two large Processes at each end, Processes. the first call'd Condiloides vel Ar­ticularis, Condiloi­des. it's received into the Sinus of the Os Petrosum, and fastned there by a strong Membranous Ligament; the motion of the Jaw depends on this Ar­ticulation; the other is call'd Corone, Corone. which from a large Basis ends in a sharp point; it lyes under the Os Ju­gale, the Tendon of the Musculus Tem­poralis is inserted into it; these Pro­cesses are in the superior part of the Bone. In its inferior part, just where it begins to turn up on each side, are its Angles, to whose outward part the Masseter Muscles are inserted, and the Pterygoidei to the interior.

This Bone is somewhat hollow within, containing a Meduller Juice.

It has four Foramina, Foramina. two of which are at the Roots of the Processes in the inside, in which a Branch of the fifth [Page 58] pair of Nerves, together with the sanguifying Vessels enter, and pass un­der the Roots of the Teeth, distribu­ting Branches to each as they pass; the other two are in the fore-part of the Chin, out of which come two Twigs of the aforesaid Nerve, which are spent on the Muscles and Skin of the lower Jaw. Alveoli. It has also its Alveoli, or Sockets for the Teeth, as the up­per Jaw.

The Uses of the lower Jaw, Vses. besides its adding to the Beauty of the Face, is to help Mastication, and serves to form the Voice.

The Teeth are the hardest of all the Bones of the Body, Teeth. having a peculiar Cortex, are smooth, and fix'd in the Alveoli of the Jaws, by Gomphosis.

They are in number about Thirty­two, Number 32. of three Ranks or Orders.

1. The Incisores, Incisores 8. or Cutters, four in each Jaw plac'd in the fore-part, and have commonly but one Phang or Root; they are also call'd by some Ri­sores, they appearing when we laugh.

[Page 59] 2. Canini, Canini 4. or Dog-teeth, by some the Eye-teeth, two in each Jaw, one on each side the Incisores; they have sometimes two Roots, but strong, and crooked.

3. The last are call'd Molares, Molares. or Grinders, in number about twenty, five on each side the Canini, and have two or three Phangs.

The Teeth are not perfected all at once, nor appear before a certain time, when they force their way through the Jaws and Gums; yet there are Observations of some who have been Born with Teeth; the first that appear in Children, are for the most part the superior Incisives, which is sometimes sooner, sometimes later, but general­ly about the seventh, eighth, or ninth Month; then in time come the Cani­ni, and lastly the Molares: When the Teeth come to about the number of twenty, there appears no more till a­bout the seventh Year, about which time there appears four more: At fourteen there comes four more, and towards the twentieth Year the last four, which are call'd Teeth of [Page 60] Wisdom, because they come at an Age, when we ought to be Wise and Serious.

The first twenty Teeth are call'd Milk-teeth, which fall or shed about the seventh Year, and new ones come in their places.

I have seen some who have had new Teeth, when they have been upwards of Sixty Years, but this is not very usual.

The Teeth have several Uses; Vses. first, they serve for Mastication, which is its chief, the Teeth being as so many Mill stones which bruise and grinde the Aliment, the Incisores cut the Mor­sel, and the Molares grinde it. Second­ly, to help Articulation of the Voice, for we see those that lose their Teeth, especially the Incisores, do not speak plain, but lisp, as we call it; they are also Ornamental.

Since we are demonstrating the Bones of the Head, Os Hyoi­des. it will not be amiss to mention the Bone which is at the Root of the Tongue, being united on­ly by Muscles; it's call'd Os Hyoides, or Ypsiloides, by reason it's like the Greek V.

[Page 61] It consists of two parts, the Body and Horns which receive the Epi­glottis.

The principal Use of this Bone, Vse. is not to support the Tongue, as some pretend, but rather to facilitate the entrance of Air into the Trachea Arte­ria, also of the Aliments into the Oeso­phagus; many Muscles also are inser­ted into this Bone.

The Bones of the Cranium being join'd together, Foramina, in the whole Cranium. there are many Fora­mina or Holes, through which Vessels pass and repass; to begin then in or­der, these appear first, and are com­monly by pairs.

1. There's a Hole which lyes be­tween the Crista Galli, Foramen, Crista Gal­li. and the Process of the Sinus Frontalis; it's a single Hole, and mentioned by no Author as I find: It may well be call'd Foramen Nasale, vel Crista Galli; through this Hole a Vessel passes from the Sinus Lon­gitudinalis of the Dura Mater to the Nose, where it becomes double, one to each Nostril; this is the way how in great Commotions of the Brain, ☞ [Page 62] the Blood sometimes streams out, and that with violence, the Vessel being then more turgid.

2. The Foramina in the Cribriforme Bone, Foramina Ethmoides for the passage of the Olfactory Nerves, and may be call'd Foramina Ethmoides.

3. The Foramina Opticorum Nervo­rum, Foramina Opticorum number two.

4. Two for the Nervi Motorii, Foramina Motorii. and other Vessels, they are very large long Holes.

5. Two call'd the Crotophite, Foramina Temp. or Temporal Holes, through which passes two Branches of the fifth pair of Nerves, to the Temples.

6. Two for the Arteriae Carotides, Foramina Carotidum which lye just by the sides of the lower parts of the Sella Turcica.

7. Two small ones, Foramina Durae Ma­tris. one on each side the Carotide Holes, call'd Fora­mina Durae Matris.

8. Two for the Auditory Nerves, Foramina Auditoria. which pass into the Antra Audito­ria.

9. Two for the Jugular Veins. Foramina Jugul.

10. Two call'd Linguales, Foramina Lingnales. through which passes Vessels to the Tongue.

[Page 63] 11. Two more for the Cervical Ar­teries, Foramina Nervor. paris 5. and also for the exit of some Nerves of the fifth pair.

12. Lastly, Foramen Medullare. the great one, call'd Foramen Medullare, for the passage of the Spinal Marrow.

All these Holes are in the Basis of the Skull, or Internal Part.

There are also several Foramina, of great use in the External Part.

1. Are two Foramina, Foramina Orbicula­ria. or Holes, one by the edge of the orbit of each Eye, call'd Orbicularia, through which passes a Branch of the fifth pair of Nerves, to the Lips.

2. The Foramina seu puncta Lachri­malia, Foramina Lachrima­lia. in the Lachrimal Bones through which the Tears pass into the Nose.

3. The Foramina Palati, Foramina Palati. they are plac'd in the fore-part of the Roof of the Mouth next the Teeth, the thin­nest Mucus of the Nose is convey'd through these two Holes.

4. Two in the back part of the Pa­late, Foramina Alia. through which Branches of the [Page 64] fifth pair of Nerves pass to the Pa­late.

As for the Foramina of the lower Jaw, I have already mentioned them in the Description of that Bone.

Demonstration IV.
Of the Bones of the Trunk.

THE next part of the Skeleton that is to be Demonstrated, Division, threefold. is the Trunk, which we shall divide in­to Three Parts, as the Back or Spine, Ribs and Breast; and lastly, the Hips, or Ossa Innominata.

The Back, or rather Spine, is com­posed of many Bones, call'd Vertebrae, Vertebrae. or Spondils, all which being join'd or united together, may not unfitly be term'd a Pyramid of Bones; but be­fore we Treat of them in particular, it will be requisite to say something of the Spine in General, Of the Spine in General. in which several Things are to be taken notice of.

1. All the Bones, Denomina­tion. from the first of the Neck, to the very Extremity of the Coccigis, are call'd the Spine, I suppose from the acute Processes each Vertebrae have, call'd Spinales.

[Page 66] 2. The figure or shape of the Spine, Figure. is of great Consideration, for if you look on its Anterior or Posterior Parts, it appears streight; but if you look on its Lateral Parts, its curved in and out: First, the Spondils of the Neck bend inwards, for the better support of the Oesophagus, also to sustain the Head in an Equilibrium, then the Ver­tebrae of the Back jet themselves out­ward, to augment the Capacity of the Thorax, that the Heart and Lungs may have a larger room to play in; towards the Loins again, they bend inwards, not only to defend the great Vessels which lye on them, but al­so to Counterballance the better the weight of the Body; the Os Sacrum bends outward, that the Pelvis be in­larged to contain the Bladder, Womb in Women, and Intestinum Rectum; and lastly, the Os Coccygis bends in­wards, that it might not be offended when we sit down, also that the Inte­stinum Rectum be tyed to it.

The third Thing to be observed in General, Bodies of the Verte­brae. or Common to all, is that the Bodies, of each Vertebra are of a [Page 67] spongy Substance, made up of many irregular bony Threads, containing a Medullar Juice, of a Convex Figure forwards, but Concave backwards, and plain above and below, being only join'd with Cartilages, which makes them Contiguous, & unites them there, which gives them a more easie moti­on, the Body also of each Vertebra gra­dually increases in bulk, till to the very Os Sacrum; for it's reasonable that those which support, ☞ should be larger than those which are supported, and at the same time as the Spinalis Medul­la passes down it grows less, losing of its bulk as the Nerves pass from it, and the Foramina Medullares of each Vertebra consequently less.

4. Each Vertebra have five Things to be consider'd, Five things to be consi­der'd in the Vertebra. which belong to all; 1. Each, as I have said, have a Body. 2. Each have a great Foramina, Foramina Spinales. through which the Spinalis Medulla passes, even to the very Os Sacrum, which may well be call'd Foramina Spinalia vel Medullaria; these holes are largest in the Vertebrae of the Neck, and so lessen as they descend, several [Page 68] Nerves, as I have hinted before, passing from the Spinal Marrow, so lessens them; but the Bodies grow lar­ger to sustain the rest, the Spinal Mar­row reaches no further than the last Vertebra of the Back, where it begins to divide into many small Filaments, which are subdivided into smaller in the Os Sacrum, Cauda E­quina, quid? where it's call'd Cauda Equina, or the Horse-tail. 3. They have each seven Processes, Seven Pro­cesses in each Vertebra. four ob­lique ones, two superior, and two in­ferior, two transverse, and an odd one call'd Acutus, vel Spinalus, by some Posterior. 4. They are join'd one to another in their oblique Processes by Ginglimus, Conjunction. and by Synchondrosis in their Bodies; also on their inside, they are lin'd with a strong smooth Membrane, which reaches from the first, to the Os Sacrum. 5. They have many Sinuffes, but the most remarkable, are those under their oblique Processes, which being united to others above the a­foresaid Processes of other Vertebrae, make certain Foramina, through which the Nerves of the Spinal Marrow passes, as also many Blood-vessels to [Page 69] and from the Spinalis Medulla; they may be aptly enough call'd Foramina Nervina. Foramina Nervina.

We come now to Treat of each Vertebra in particular; Of the Ver­tebrae in particular. Number 25. the Vertebrae are in number twenty-five; that is, se­ven of the Neck, twelve of the Back, five of the Loins, and one of the Os Sacrum, to which is annex'd the Ossa Coccygis.

The Neck has seven. Seven of the Neck.

The first is call'd Atlas, 1. Atlas. by reason is sustains the Head, as Atlas was sup­posed to do the Heavens; its transverse Processes, as also all the other of the Neck, are not so long as those of the Back; it's Articulated to the Condi­loid Processes of the Os Occipitis, by its superior oblique Processes, in which are two Sinus's that receives the afore­said Condiloid Processes; this Articu­lation is a sort of double Arthrodia, so is only capable of Flexion and Exten­tion; it has very little, or no Body, but within has a small Sinus to receive the Dens of the second Vertebra; this Sinus is lin'd with a strong Ligament, [Page 70] which fastens the aforesaid Dens, the Spinal Process is a very little blunt knob, but all the other Spines of the Neck are forked, except the last. It has a small round Process in its upper part where the Body should be, from which passes a small Ligament, to ano­ther small round Process between the Condiloides of the Occipital Bone, close to the Foramen Medullare.

The second Vertebra is call'd Denta­ta vel Epistrophous, 2. Dentata. because between its two superior Processes, springs ano­ther very hard one, call'd Dens, being like a little Tooth, which being re­ceived into the above-mentioned Sinus of the first Vertebra, and encompassed with strong Membranous Ligaments; this moves in the Atlas as an Axis, as the Flexion and Extention depend on the first Vertebra with the Head; ☜ the Circular Motion depends on this and the first: When a Luxation happens here, the Neck is said to be broke.

The five following have no particu­lar Name, and are much like one ano­ther, only increasing a little in bigness, and the Spinal Process of the last is [Page 71] not fork'd, beginning to grow some­what like those of the Back; the trans­verse Processes, and spinous ones, are somewhat rough, for the better in­sertion of many Muscles, which are fastned there.

All the Vertebrae of the Neck, Foramina Vertebra­rum Colli▪ have two small Foramina each, which lye in the Head of the transverse Processes, serving for the passage of the Verte­bral Arteries.

Their oblique Processes have this ob­servable in them, their superior ones are somewhat hollowish, to receive the inferior Convex ones, that the moti­on of the Neck be freer.

The Back has twelve Vertebrae; Back 12. yet I once saw a Skeleton that had thir­teen, and thirteen Ribs; they are bigger than those of the Neck, but less then those of the Loins; their Spi­nal Processes are not fork'd but pointed, and lye one over another; the trans­verse are short, but large, and blunt, and have a Cavity to receive the Heads of the Ribs; the oblique are sharp, and smooth, and so conse­quently little motion, Vertebrae Costales. these are call'd [Page 72] the Costal Vertebrae; the eleventh Ver­tebra has its spinal Process, not lying over the other, as those above it.

The last Vertebra of the Back has this to be observed in it; it receives none, but is received, both by the eleventh of the Back, and first of the Loins; on this depends the greatest motion of the Back.

The five of the Loins are larger than those of the Back, Loins 5. and their Articu­lation looser, their transverse Pro­cesses are more long and fine than those of the Back, which serve as Ribs, as it were, yet the first and fifth are shorter than the rest; their Fora­mina Nervina are excavated only out of the lower Vertebra, N. B. whereas those of the Back equally out of both, but those of the Neck only out of the su­perior; their posterior Spines, are short, blunt and thick, a little broad, and turn a little upwards, that the bending of the Body be no way hin­dred; and whereas in the other Ver­tebrae, the upper oblique Processes re­ceive the lower, in these the lower re­ceive the upper.

[Page 73] The first of these Vertebrae is call'd Renalis, Renalis. the Kidneys being lodged at the side of it; the other four have no particular Name.

The Os Sacrum, Os Sacrum. or holy Bone, so call'd, as some think, because the An­tients used to save this part as Sacred in Sacrifices; but I think rather from [...], as the Greeks call it, which signifies Magnum, as well as Sacrum, it being the biggest Bone of all the Spine. It's immoveable, and serves as a Basis or Pedestal to the whole Spine; it's of a somewhat triangular Figure, with the point downwards; it's Concavous within, which helps to form the Pelvis, also smooth; be­hind it's Convex, and unequal, many Muscles arising, and being inserted here, it seems as if it were composed of five or six Bones, (as indeed it is in Infants) its Ossification beginning at so many points, but its edges, or ra­ther, if you will, its transverse Pro­cesses look but like one continued Bone, as it is; the Foramen Spinale towards its lower part is very small; its Foramina Nervina are before and [Page 74] behind, and not on the sides, as in the other Vertebrae; its spinal Processes are very small, the last being only a small round Protuberance, it ob­lique Processes are hardly visible, ex­cept the superior ones; the parts which compose the Os Sacrum, are plac'd in the number of the Vertebrae, not by reason of their use, but because of their resemblance, for otherwise they are immoveable: The Os Sacrum may be said to be divided into five Vertebrae of different bigness, whereof the superior is biggest, they diminish­ing as they descend, the last being the least; these seperate easily in Infants, by reason the Cartilages which unite them, are not fully ossified; but in A­dults, they all make up but one intire Bone.

This Bone seems to have several Uses, Vses. the first is, as I have already re­mark'd, to serve as a Foundation to the whole Spine. Secondly, to help to contain the parts of the Hypogastri­um, by forming Cavity, as I have said. The third to defend them; the fourth to Articulate the Bones of the [Page 75] Hips; the fifth to give Origin and In­sertion to many Muscles.

To the end of this Bone are annex'd two or three little Bones call'd Ossa Coccygis, Ossa Coc­cygis. the Cuckow's Beak; some call them the Rump-bones: They have a somewhat loose Articulation, and tyed by Cartilages one to ano­ther, the last is the smallest: They have this loose Articulation, that they may give way to the Foetus in the Birth, therefore in Women these Bones are always more bent back­wards than in Men; they end in a Cartilaginous point, to which is tyed the Intestinum Rectum; they have no thing more material in them, having neither Process nor Cavity.

We shall now proceed to the Bones of the Breast and Ribs, Bones of the Breast. which is the second Division of the Trunk.

The Ribs are twenty-four in num­ber, Ribs 24. twelve on each side; to be well-instructed in all which concerns the Ribs, we must observe several things, as their Substance, Figure, Connexi­ons, Parts, Division and Use, of all which in order.

[Page 76] The substance of the Ribs is partly Bony, Substance of the Ribs. and partly Cartilaginous, that end next the Vertebra, being of a har­der and more solid and thick substance than that towards the Sternon, which is flattish, so less capable of being broke; sor that end towards the Ster­non being more spongy in substance, all the Ribs end towards the Breast by Cartilages, increasing in length as the Ribs descend; and those Cartilages of the superior Ribs, are harder than those of the inferior; sometimes these Cartilages grow bony in Old People, so that they cannot be separated by a Knife.

The Ribs have a sort of Semicircu­lar Figure, Figure. making a sort of Arch; when two are together, they make a kind of a true Circle, Concave inward­ly, to form the Capacity of the Tho­rax, and to contain the Lungs and Heart, and Convex outwardly, to re­sist outward force; the farther they depart from the Sternon, the more round they are in their own Body; they are not equally big, for the supe­rior are shorter, the middle biggest of [Page 77] all, and the inferior one least of all; their upper sides are thick, blunt, and broad; one edge is call'd the interior, the other the exterior Lip; their un­der edges are sharp, having in their inside a long Sinus, or Furrow, in which lye the Intercostal Vessels.

The Ribs are Articulated by their Extremities, Articulati­on. both to the Vertebrae of the Thorax, and Sternon; that Articu­lation with the Back is moveable, the other not; the long Head of each Rib is Articulated by a single Arthrodia; it has a small Protuberance cloathed with a Cartilage, which head is re­ceived into a Sinus of the transverse Process of the Vertebra; 'tis this Pro­cess which supports the Ribs, and hin­ders them from coming lower in Ex­piration: You must observe, N. B. that the back-part of every Rib is higher than the fore-part, till the Cartilage be join'd, which turning a little up, makes the two ends of an equal height, so that by the rising of the Ribs, the Breast is enlarged. We must also take notice, that almost all the Ribs have a Communication with the [Page 78] Sternon, either directly or indirectly; that is, the superior ones are by a di­rect insertion, but the lower by an in­direct, which is by Cartilages adhe­ring to the superior.

All the Ribs make a sort of Angle by their Cartilages towards the Ster­non, which serves to increase the Spring of the Cartilages, that the Ribs be brought down again, having been rais'd in Inspiration. It some­times happens, though seldom, that these Cartilages are ossified, ☜ which occasions an Incurable Asthma; the last, or lowest Rib in Man, have no Cartilage as the rest; the lower the Ribs, are, longest and more movable, N. B. because Respiration in Man is downwards, but in Birds up­wards.

The Ribs are commonly divided in two sorts, Ribs of two sorts. as true or false, but I think they may well be all accounted true, except the last, (being join'd mediate­or immediately to the Sternon by Car­tilages) which has none, so only may be term'd a false Rib; however it be­ing a common received Opinion, I [Page 79] shall make the division: the long or true are seven on each side, True 14. and are the superior ones; the first of which has no motion at all, it being as a prop for all the rest, but as they de­scend they increase in motion; they are Articulated to the Vertebrae of the Back by a sort of double Arthrodia, which makes a Ginglimus, and to the Sternon by Synarthrosis, the three low­est of which are by some call'd the Pectoral Ribs. Costae Pe­ctorales.

The false or bastard are five on each side, False, 10. the four uppermost of which have at their Extremities towards the Sternon long Cartilages, bending up­wards, and cleaving only one to ano­ther; that is, the lowest to the supe­rior, so not directly united to the Sternon, as the first seven are; which was the Reason the Antients gave them the Name of Spurious: The last has no Cartilage at its end, the edge of the Diaphragme being tyed to it.

All the Ribs, as I have already de­monstrated, are received both into the transverse Processes, and body of the Vertebrae; except the two or three [Page 80] last, which are only received into the body of the Vertebrae.

The Ribs are to defend the Heart and Lungs, Vse. &c. from all sorts of ex­ternal Injuries, so that they be not prest, but have free motion, which were it not bony, would be always in danger of being offended; they also serve to sustain the Respiratory Mus­cles.

The Cartilages of the Ribs have this Use, Vse of the Cartilages. that is, when the Ribs are drawn something upwards in Inspiration, they draw them down again with a sort of Spring; for all Cartilaginous Bodies are indued with a sort of Ela­sticity, so that they always recover their first Figure.

This Mechanism is observed in va­rious Animals, ☜ for in Birds the Ster­non is immovable, because the flying Muscles arise from thence; so that if the Sternon had any thing to do in Re­spiration, it would be hinder'd; therefore Nature has contrived another Artifice, which is this, between eve­ry Rib there's a little Bone, plac'd somewhat obliquely, so that if one [Page 81] moves, the other follow by con­sent.

All these Birds have no Diaphragm, ☞ but instead thereof two Bladders, which reach to the bottom of their Bellies, they serve for the Diaphrag­ma, and also help to keep them sus­pended in the Air: Those Creatures which have a Diaphragma, breathe downwards, but Birds, &c. which have none, breathe upwards.

In Amphibious Creatures, as the Tortoise, &c. their shell is in place of Ribs, and Frogs have only one Rib on a side, to defend the Lungs.

The Breast-bone is call'd Sternon, Sternon made up of three Bones. or Os Pectoris, situated in the middle of the Anterior part of the Breast, com­posed of two or three Bones, having the Productions of the Cartilages of the Ribs inserted into their sides, of a reddish fungous Substance.

To consider it well, it must be exa­mined at two different times; for in Infants it's almost all Cartilaginous, except the first Bone where the Clavi­culae are fastned. In Old People I have seen it all ossified, except the first [Page 82] with the second at its juncture, but in those of Middle Age, partly Bony, and partly Cartilaginous, the supe­rior Bone always ossifies first, and the inferior last. In the Sternon of Infants you may perceive seven or eight Jun­ctures, as if so many Bones, but in the seventh or eighth Year, they uni­ting, make up but three or four at most.

The first or superior Bone of the Sternon, First Bone. is more thick and solid than the rest, made in the shape of a Cres­cent almost, at each side of its superior part, it has a Sinus to receive the head of the Clavicula; at its top it has a Lu­nated Sinus call'd Jugulum; Jugulum. it has al­so a small long Sinus on its inside, to give way to the Aspera Arteria: It's immovable.

The second Bone is narrower, Second Bone. lon­ger and thinner, having at its sides many Sinosities, to receive the Carti­lages of the Ribs.

The third Bone is less than the se­cond, Third Bone. but broader, at the lower end of which is annex'd a Cartilage call'd Xiphoides, vel Mucroconita, vel Ensi­formis, [Page 83] the Sword-like Cartilage; Cartilago Ensiformis. it's of a Triangular Figure, it serves to defend the superior Orifice of the Sto­mach: It's this place which is call'd Scrobiculus Cordis, the Heart-pit; the Diaphragma is also fastned to it; a strong Ligament of the Liver, call'd Suspensorium, ☜ is tyed to it, for in In­spiration the Ribs being draw up­wards, then the Liver by its weight keeps this from moving, and when in Exspiration the Ribs assume their for­mer Figure, this by its Cartilaginous Spring assumes his also.

The Uses of the Sternon are, Vses of the Sternon. first, to unite the Ribs, that their motion may be all at one and the same time, also to receive the Clavicula: Lastly, to fasten the Mediastinum, which is a Membrane that divides the Breast in two.

The third part that compose the Trunk, Ossa Inno­minata. are call'd Ossa Innominata, be­cause of a very strange Figure; they are in number two, one on each side of the Os Sacrum, having where they are united to it, many Depressions and Risings, for their greater Strength and [Page 84] Connexion, Articulati­on. being Articulated before by Synchondrosis, so make up that Ca­vity call'd the Pelvis, Pelvis. which contains the (Womb in Women) Bladder, and Intestinum Rectum, with other of the Guts.

In Children each Bone consists of three, Each con­sists of three in Children. all of them meeting in that deep Cavity, call'd Acetabulum, which receives the head of the Fenier, but as we grow in Years they all make but one Bone, yet then, for better distin­ction, nam'd as three, as the Os Ile­um, Ischium, and Pubis, of all which in order.

The Ileum is the superior part of the Bone, Os lleum. so call'd, because most part of the Ileum-Gut lyes on its Internal Face; from it's External arise the Musculi Glutei: It's the biggest of the three, and join'd with the Os Sa­crum.

Things to be consider'd in this Bone, Spina Ilei. are, first, its Figure, which is Semi­circular. Secondly, its top, which is call'd the Ridg, Comb, or Spine, be­ing covered with a Cartilage: Its In­ternal [Page 85] Face is Concave, and its Exte­rior Convex: It has three Protube­rances, being rather so many parts of the Spine; Three parts of the Spine. one forwards, call'd Spina Anterior Superior; another below, call'd Spina Anterior Inferior, less than the former; and a third behind, call'd Spina Posterior.

The Os Ischium, Os Ischium or Coxendicis, is the lower part of the Os Innomina­tum, in which is to be consider'd two parts; first, It's Superior, which makes up the greatest part of the Cotu­la, or Acetabulum. Secondly, Its In­ferior, or lower part, which we sit on, which is call'd Tuberositas Ischii; Tuberosi­tas. it has a Sinuosity on its inner side, where the Musculus Obturator Internus winds about; the Muscles of the Penis, and Elevators of the Anus, have their Ori­gin from the Tuberosity of the Is­chium.

The Os Pubis, Os Pubis. or Pectinis, by us the Share-bone, is the fore-part of the Os Innominatum; it's join'd forwardly to its Fellow by Synchondrosis, the hinder part of it forms part of the Acetabulum; [Page 86] the superior part is call'd the Spine, to which the Muscles of the Abdomen are fastned; where this joins with the Ischium there's large Foramen, call'd Ovale, Foramen Ovale Ossis Pubis. cover'd with very a strong Li­gamentous Membrane; above this Foramen there's Sinus, by which the Crural Vessels pass to the Thigh.

All these Bones being join'd toge­ther in their middle, make up that deep Cavity call'd Acetabulum, vel Co­tula, in which the head of the Os Fe­moris enters, which is tipt with a Cartilage, call'd Supercilium.

These Bones are more ample and large in Women than Men, Ossa Pubis, largest in Women. and those which have them most advanc'd, have the easiest Labour.

The Antients believed, that in La­bour the Ossa Pubis separated for the more easie Delivery of the Birth, The Ossa Pubis do not separate in Labour. nay, Bartholinus is of this Opinion, for he says, that in a Woman newly Deli­ver'd, you may divide them with the back of a Knife; but I presume it's not so, for they separate not the least; 'tis only the Os Coccygis which gives [Page 87] way a little by bending backwards, for most pain is felt when the Foetus passes by the Fundament; yet some have a more loose Articulation of their Bones, and so perhaps might bring them into this Error.

Demonstration IV.
Of the Bones of the Superior Extremities.

I Have Demonstrated all the Bones which make up the two parts of the Skeleton, there remains now only the third part, which is those of the Extremities.

The Extremities, Extremi­ties, Vpper and Lower. or rather the Limbs, are either Superior, as the Arms; or Inferior, as the Legs.

We will begin with the Superior; but first I must inform you, that since both Extremities are double, I shall only speak of them in the singular num­ber, for by demonstrating one side, you at the same time shew the other.

Although there be no part which does not furnish us with some Subject of Admiration, yet we must all agree, that the Arm hath as great a share, if not more, than any other; for which reason Aristotle call'd it the Organ of [Page 89] Organs, and the Instrument of Instru­ments; and since Nature has given to all Animals, something particular, either to defend themselves against others, and preserve themselves from external Injuries; or else to offend; we may say then, that Man has re­ceived two things preferable to Ani­mals, to wit, Reason and Hands, the one for Counsel and Conduct, the o­ther for Execution of our Will; 'tis these Hands which gives him the So­veraign Command over all Creatures be he never so Cruel, Strong, or Swift; for of what Advantage would all our Reason and Conduct be, if we had not Hands to perform what Rea­son dictates: I could say much more on this Subject, but that I am here on plain Demonstration, and not Philo­sophizing.

The Arm, Division. Arm, five parts. generally so called, has five parts, as the Clavicula, Scapula, Shoulder, Arm, and Hand, of all which in due course.

1. The Clavicula, Clavicula▪ which some place among the Bones of the Spine, but I [Page 90] think it rather belongs to those of the Arms, as I shall shew in its use, the whole motion of the Arm depending on this Bone; It's call'd Clavicula, I suppose, being a diminutive from Cla­vis a Key, because the Keys in old time were like an s Figure. in Padua they have such sort of Keys still, as I am in­form'd by those who have been there; it's not so crooked in Women as in Men; Articulati­on. it's Articulated by one end to the Acromium of the Scapula, and by the other to the upper part of the first Bone of the Sternon; by a sort of Arthrodia, yet has but little motion; the more crooked these Bones are, the more force and agility has the Arm. Substance. It's hollow in the middle, and contains Marrow, as all long Bones, but towards the ends Spongy; that end towards the Acromium is not very thick, but rough, and unequal, the end towards the Sternon smoother: It's also here outwardly Convex, but inwardly Concave, to give way to the Vessels which pass under it, other­wise it would have prest them; but towards the Acromium, ☜ Convex in­wardly, [Page 91] and Concave outwardly, for the more convenient situation of the Deltoid Muscle, which would other­wise appear too bulky, and make the Breast look deform'd.

They serve to uphold the Scapula and Humerus from falling on the Breast, Vse. which they do when this Bone happens to be Fractured; the whole motion of the Arm depends also on this Bone; for Brutes having no Cla­viculae, cannot move their Fore-legs so readily as Man, or as some Animals which have them, as Monkeys, Squir­rels, &c.

2. The Scapula, Scapula. or Shoulder bone, is situated on the back-part of the Tho­rax, being only fastned with Muscles, (so more loose, that the motion be freer and easie) except in its Acromi­um where it's Articulated with the Clavicula; it's of a Triangular Figure, Figure. whereof two Angles are Posterior, and one Anterior, Its inward Face is Concave, as well to accommodate it self to the Ribs whereon it lyes, as to contain a Muscle, but outward Gib­bous, thicker on its edges than in the [Page 92] middle, ☜ being there transparent, and very thin; so that in a Caries of that part we cannot expect Exfoliation, no Medullar Glands being there, it's nou­rished from its sides.

Parts to be consider'd in this Bone, Processes, three. are first, its Processes, which are three, first is a thin, but rising Process, in the middle of its outside, extending all its length, it's call'd the Spine; Spine Acromium its Point or Extremity is call'd the Acromium, in which is a flattish Sinus to receive the Clavicula: Some say that this Pro­cess is a distinct Bone from the Scapula, because in Infants its only Cartilagi­nous, which ossifying by degrees, makes up but one Bone; the second is less, and plac'd at the superior part of the Neck, which advances above the Head of the Bone of the Arm: It's curved, and call'd Coracoides, Coracoides Ancyroi­des the Crows-bill, or Ancyroides, some call it only Processus Curvatus, it streng­thens the Articulation of the Humerus. The third, or middle one, is call'd Cervix, Cervix. is which in a somewhat flat Sinus to receive the head of the Hume­rus, call'd Glenoides; the Humerus is [Page 93] tyed to it by a strong, but somewhat loose Ligament; the edges of this Si­nus is tipt with a Cartilaginous Liga­ment, which hinders the Humerus from being too easily Dislocated; there's also a strong Ligament from the Acromium to the Processus Cora­coides, which, together with the A­cromium, ☞ hinders the Humerus from being too easily Dislocated upwards, except this Ligament or the Acromiune be broken.

The edges of this Bone are call'd Costa. Costa.

It has three Angles, Angles, three. 1. The Infe­rior. 2. Posterior. 3. Cervix; that part which reaches from the Posterior to the Inferior Angle, is call'd the Ba­sis of the Scapula. Basis.

It has two notable Sinusses Sinusses. one on each side the Spine, where the Musculi Infra, and Supra Spinati lye; the lower Sinus is largest; in its inside Concave part lyes the Musculus Subscapularis, vel Immersus.

The Scapula has many Uses; Vse. first, it gives Origin to many Muscles, it fa­stens also the Arm to the Body, and [Page 94] serves to support it, to the end it may have all its motions.

The third part of the superior Limb is the Os Humeri, Humerus. or Shoulder­bone, it's the strongest and largest of all that compose the Arm; it's long and round in its fore part, but some­what flat behind; its superior part is Articulated to the Cervix of the Scapu­la by Arthrodia; Articulati­on. at its lower end with the Cubitus by Ginglimus; it al­so touches the Radius by Arthrodia.

To examine the parts of the Hume­rus, you must consider its Extremi­ties, Parts to be consider'd. and Body.

The Body is long and round, with­in it contains a Marrow; Body. its Figure is not absolutely streight, but somewhat hollow inwardly, and bunching out­wardly, to fortifie it in its Actions; there is observed a Line which de­scends and terminates in two Pro­cesses, which serve to fasten the Mus­cles inserted here.

The superior Extremity of the Hu­merus is bigger and more spongy than the Inferior; Superior Extremity. and contains a Medullar Juice; it's call'd the Head, cover'd [Page 95] with a Cartilage: It's encompassed on all sides with Ligaments and Mem­branes, which proceed from the Gle­noid Cavity of the Scapula; a little be­low this Head, Processes. there's a round part a little smaller, call'd the Neck; there's at the hinder part of this end two rough unequal Processes, into which several Tendons and Ligaments are inserted; so that great Care ought to be had in Wounds, or Ulcers of this part, lest you mistake the Roughness for a Cariosity; N. B. between these inequa­lities there's a long Slit, or Scissure, in which the Tendon of the Musculus Biceps passes.

The Inferior Extremity of the Hu­merus is less, flatter, and harder than the other; it has three Processes, two whereof are call'd Condyli, Condyli▪ the Exte­rior and Interior: The Bone seems here to be divided in two parts. The third, or middle Process, is large, and call'd Trochlea, Trochlea. the Pully; it has two large Sinusses, which receive the Pro­cesses of the Vlna, to which it's Arti­culated by Ginglimus; the back Sinus is large and deep, which receives the [Page 96] Olecranon, but that on its fore part smaller.

The fourth part, Brachium, two Bones. or that which is strictly call'd the Arm, is composed of two Bones, the biggest and longest call'd Vlna, the lesser Radius; for had this part been made up only of one Bone join'd by Ginglimus, we could do nothing else but extend and draw up the Arm, and not turn it upwards and downwards, which is perform'd by means of the Radius, for which end it's Articulated by Arthrodia.

The two Bones are not both of a bigness, for which some distinguish them by the Names of Major and Minor Focile; in their middle they are somewhat distant the one from the o­ther, for the more Commodious Situa­tion of the Muscles, Passage of the Ves­sels, and principally for the Ease of Motion.

1. The Vlna, or Cubitus, Ulna. so call'd, by reason it's this Bone which makes the Elbow; it's biggest at the superior part, and had two large Processes, that in the back-part is call'd Olecranon▪ Olecranon. [Page 97] vel Ancon, which when the Arm is extended, is received into the large Posterior Sinus of the Trochlea, so stops the Arm from going further back­wards, it's otherwise call'd the El­bow; the other is less, and received into the fore Sinus of the Trochlea, it stops the Arm from being bent too close forward; below this is another very small Process, into which the Tendon of the Musculus Biceps is in­serted.

It has two small Sinusses, Sinusses. the Lat­teral one receiving the Head of the Radius, the other is between the two large Processes, and receives the Tro­chlea of the Humerus; it may be call'd Sigmatoides, because it resembles the Greek Letter Sigma.

At the body, Three An­gles in its Body. of middle of this Bone, there's observed three Angles, where­of the Inferior is call'd the Spine, and is very streight; the other two are oblique, the one of which is the Ante­rior Angle, the other Posterior; one side is very smooth and equal, the o­ther pretty rough, some Tendons be­ing inserted there.

[Page 98] The Inferior part of this Bone has two Eminencies, and one Cavity; the first of the Eminencies is seated at the lateral part, and is received by the Glenoid Cavity of the Radius: The second is at the very Extremity, and may be call'd Styloides, Stylodes. it serves to strengthen the Articulation; the Ca­vity or Sinuosity is at the end of the Bone, and helps to make the Arthro­dia with the Carpus: This Bone at its superior end receives the Radius, but is received by the Radius at its lower end.

The Radius Radius. is the second Bone of the Arm, (or as some call it, the Fore-Arm) so call'd, because it resembles the Spoke of a Wheel; Articulati­on. it's Articula­ted in its superior part, two manner of ways: First, with the External Con­dyl of the Humerus. Secondly, with the Ulna, and both by Arlhrodia: It's likewise Articulated two manner of ways in its Inferior part, either with the Bones of the Carpus at its Extremi­ty, or with the Vlna, on its latter part: The Radius is smallest in its Superior, but largest in its Inferior part.

[Page 99] The Things to be observed in its Superior part are these; Superior part. First, its Head, which is round and polished, at the end of which is a Glenoid Cavi­ty, which as I have already remark'd, receives the External Condyl of the Humerus; the Neck is somewhat long. Now this is very observable, ☞ that the Ligament which comes from the other Bone to join it, is not inser­ted in it as in other Bones, but only encompasses this Neck as a Ring, so that it may turn, Ligamen­tum Admi­rabile. for its Prone, and Supine Motions, which had the Liga­ment been inserted into it, it could not have done, yet at the same time it's strong enough to keep it firm; the whole motion of the Wrist is per­form'd by the Radius; the Tuberosity or Eminence is seated just below the Neck, and is received into the lateral Superior Sinus of the Ulna.

In its middle it has an obtuse Angle, which some call the Spine, which gradually grows bigger as it inclines towards the Carpus, different from the Cubitus, Body. which diminishes: It's in this that we may admire Nature, which [Page 100] not being able to avoid making these two Bones unequal in their Extremi­ties, has found means to make the Arm equally strong in all parts, by placing the weakest part of one Bone against the strongest of the other.

At its Inferior part many Sinuosities appear, Inferior part. which are as small Gutters, that so the Tendons be not incommo­ded; it has also a Cavity at its Extre­mity, which receives one of the Bones of the Carpus; at its lower end it has a blunt Process, Mastoides. call'd Mastoides: from the Internal Angle of this Bone, there's a long broad Ligamentous Membrane, which unites it to the In­ternal Angle of the Ulna, according to its length.

The Ulna serves only for Flexion and Extension, Vse of the Radius and Ulna. and the Radius for Pronation and Supination.

The fifth and last part of the Arm, 5. Hand. generally so call'd, is the Hand, which is subdivided into the Carpus, Metacar­pus. and Fingers.

The Carpus, Carpus, eight Bones. or Wrist, is composed of eight small Bones plac'd in two ranks, four in a rank, three of the [Page 101] first rank are united very close on their sides, the two greatest of which are received into the Cavity of the Ra­dius by Arthrodia, for the motion of the Hand in their Inferior part, they touch the three Bones of the second rank of the Carpus; the third of the first rank which is next in bigness, and received in the Cavity at the lower Extremity of the Ulna; the fourth of the first rank which lyes on the out­side, a little out of its rank, is the least of the four: The four Bones of the se­cond rank are join'd together on their sides by Harmonia, as the Bones of the first rank are, also one to another so; but at their ends, to the Bones of the Metacarpus by Enarthrosis, having an obscure motion: The first Bone of this rank is seated more within the Hand, that the Thumb be better su­stain'd; the second and third sustain the first and second Bone of the Meta­carpus; the fourth Bone of this second rank sustains the third and fourth Bones of the Metacarp, by its two Gle­noid Cavities: All these Bones are Convex on the back-part, but hollow­ish [Page 102] within, ☜ for the more safe passage of the Vessels, and Tendons of the Musculi Flexores, being likewise guard­ed by the Ligamentum Anulare which covers them, Ligamen­tum Anu­lare. and joins together all these Bones.

The Metacarpus is composed of four long hollowish Bones, Metacar­pus, four Bones. containing Marrow in their Internal Sinusses; there are some who make five Bones of the Metacarp, and for that end add thereto the first Bone of the Thumb, but it ought not to be numerated a­mong those of the Metacarp, it having a manifest, but the others a very ob­scure Motion.

These four Bones are united by their Superior Extremities with the Carpus, Articulati­on. as I have already mentioned, by means of strong Cartilaginous Ligaments, and with the first Bones of the Fingers by Arthrodia; they also touch one a­nother in their lateral Parts, especially towards the Carpus; about the mid­dle they are a little separated to give way to the Musculi Interossei: They are Convex, and smooth outwardly, [Page 103] but Concave inwardly; all their Ex­tremities are tipt with Cartilages.

These four Bones are not of an equal bigness, for that which sustains the Index is the largest, that which su­stains the middle Finger less, and so on to the very last, which is least of all.

The Fingers, Fingers. counting the Thumb, are five, having three Bones each; these Orders may be well call'd Pha­langi Digitorum, Phalangi Digitorum. the first largest, the second less, the third least of all; their outward Face round, but plain, and even within, Articulated to each o­ther by Ginglimus, except the first rank, which are join'd by Arthrodia to the Metacarp, and so have all sorts of Motion, but the other Joints have only Flexion and Extension: The least Bones are not hollow as the rest, but spongy.

The Greeks call the Hand in general Cheir, but the Thumb Antichier, as much as to say, an opposite Hand: The second Finger, counting the Thumb as one, is call'd Indicator, because we are apt to point it, when we intend to [Page 104] shew something: The third is call'd the Middle-Finger, because of its situa­tion, and is the longest of all: The fourth is call'd the Annular, by reason Rings are used the most upon this Fin­ger: The fifth and least is call'd the Auricular, being most fit to pick the Ear with.

I will not speak here of the Ossa Sesa­moidea, which are sometimes found in the Joints of the Fingers, till we explain the Bones of the Toes.

Demonstration. V.
Of the Bones of the Inferior Extremities.

WE come now to Demonstrate the Bones of the Inferior Limbs, which is the last part of the Osteo­logy.

The Leg, Division. generally so taken, may be divided into the Bones of the Thigh, Leg, and Foot.

We shall begin with the Thigh­bone, Os Femo­ris. which is but one in each Leg: It's the longest largest, and strongest Bone of the Body, being form'd to su­stain the weight of the whole Body; some saying that the word Femur is derived from the Verb Fero, to carry or bear; it's imbow'd a little on the fore-part, but hollow in its back.

We must examine in this Bone se­veral Things. Things to be examined in it.

[Page 106] First, At its upper end it has a great round head, cover'd with a smooth Cartilage, Articulati­on. and received into the Ace­tabulum by Enarthrosis, and tyed there­in by a short, but strong round Liga­ment, which is fastned in the very middle of the Head; Caput. under this Head lyes the Neck, Cervix. which is long, and lyes obliquely, otherwise the Head coud never have entred conveniently into the Acetabulum, considering its posture in the Skeleton; and also the Neck carrying it self outwardly, puts these Bones the one from the other, and so causes that the Body be carried more conveniently and surely.

At this Extremity or End lyes two Apophyses, Trochan­ters. behind the Neck, call'd Trochanters, which are derived from the Greek work [...], which signi­fies to turn, because many of the Mus­cles of the Thigh, especially the Rota­tores, are fastned to these Protube­rances, the Anterior and Upper one is the biggest, the Posterior and Lower the less: the outward part of this Bone is smooth, but rough within, many Muscles arising from thence: This [Page 107] Bone has a large long Cavity all its length, full of Marrow; it's of a crooked Figure, ☞ so that Surgeons in Fractures of this Bone, ought well to consider its sound Figure: Towards its lower end it grows thicker and lar­ger, ending in two large heads, which are received into the two shallow Si­nus's of the Tibia; between these two Processes is a Sinus which receives a rising Process of the Tibia, so that here the Thigh-bone is Articulated by a loose Ginglimus; the fore-part of this Articulation is call'd the Knee, the Po­sterior the Ham.

The Leg, Leg. strictly so call'd, is com­posed of two Bones, the greater and internal call'd Tibia, the lesser and ex­ternal Fibula, by many also Focile ma­jus & minus.

The Tibia is the biggest, Tibia. hollow within, and full of Marrow, it's partly Triangular; its sharp Angle of Spine makes that we call the Shin; it has a ridge like a Process at its upper end, which is received by the Sinus at the extremity of the Femur; on each side of this Process, there's two longish, [Page 108] shallow Cavities, to receive the two lower Eminences of the Femur: These shallow Cavities are deepned by a lu­nated Cartilage, which is thick about the edges, but grows thin towards the Centre; as this Bone approaches towards the Tarsus it lessens, but grows more solid; at the lower part of the Tibia there's notable Process which makes the Internal Ancle, Malleolus Internus. which hinders the luxation of the Foot, in keeping in firm: At the bot­tom of the Tibia there's a Sinus, which receives the Convex head of the Astra­galus; this Bone supports the whole Body.

The Fibula, Fibula. or Perone, is as long as the other, but much slenderer, plac'd on the outside of the Leg; its superior head reaches not quite to the Os Femoris, but has a shallow Sinus on its side, which receives a small lateral Process of the Tibia; this Articulation is fortified with a Ligament; its Body is of a Triangular Figure as well as the Tibia, but a little more irregular; the lower end is received by the Tibia, and extending it self to the side of the [Page 109] Astragalus, Malleolus Externus. makes the external Ankle; both these Ankles, or rather Processes, hinder the Talus from being too easily dislocated.

These two Bones separate a little one from another in their middle, to make room for the Muscles and Ves­sels.

Upon the Knee lyes a small round Bone, Rotula. gibbous, and plain without, but hollowish within, about two Inches broad, somewhat like the Boss of a Buckler, the middle being thick, and thinning towards its edges, call'd Rotula, Patella, the Knee-pan; it's movable, and Articulated by a sort of Ginglimus, cover'd with the Aponeu­rosis of four Muscles, being the Exten­ders of the Leg; internally it has a very smooth Cartilage, to facilitate its motions.

Some believe it's to strengthen the Articulation of the Joint, Vse. but it's no such thing, it being rather plac'd to cause greater force in extending the Leg, by reason the Tendons of the Musculi Extensores pass over it; ☞ for if the Tendons had not this hillock, as [Page 110] it were, to pass over, but lain flat on the Bones, they could not have had so much force, as by this means to ex­tend the Leg.

It's of a hard Substance, Substance. but some­what spongy within, and tyed loosly by Ligaments.

The Foot is subdivided into the Tar­sus, Metatarsus, Ossa Pedis. and Toes.

The Tarsus is made up of seven Bones, Tarsus. differing much in shape and bigness; four of which have particu­lar Names, the other three no other but Ossa Cuneiformia in general.

First, The Talus, vel Astragalus, Talus. is of a very strange figure, in which is to be consider'd its six Faces: First, the Superior, which is very smooth and convex, Articulated with the Ti­bia, hedged in by both Malleoli: Se­condly, its Anterior, which is a great head which enters the Cavity of the Os Naviculare, with which it's strong­ly Articulated: Thirdly, the Poste­rior, which has a Protuberance recei­ved by the Os Calcis: Fourthly, the In­ferior, which is rough and unequal, [Page 111] rising in some places, and sinking in others: The fifth and sixth are the two Lateral Faces, hedged in, as I said, by the Malleoli; it serves as a Basis to sustain the Tibia, which sup­ports the whole Body.

The second Bone is the Os Calcis, Os Calcis. or Heel bone, the biggest and largest of the seven, but most porous of all; it's this Bone which hinders the Body from falling backwards, being seated at the Posterior part of the Foot; it lyes uner the Talus, to which it's Articulated; it's also join'd with a flat head to the Os Cuboides; behind it has a long Process, to which is tyed the great Tendon, call'd Nervus He­ctoricus, vel Achillis; it has a large Sinus on its inside, by which the Ten­dons pass under the Foot, it's very un­equal on its outside, for the insertion of Ligaments and Tendons.

The third is call'd Os Scaphoides, Cymbiforme, vel Naviculare, Os Navicu­lare. the Boat-like Bone, behind it has a large Cavi­ty, wherein the head of the Astrga­lus is received: but before it has three Eminences, which unites it to the Ossa Cuneiformia.

[Page 112] The fourth has a somewhat un­equal Figure of six irregular sides, Os Cuboi­des. therefore call'd Cuboides, the Die-like Bone, by some Multiforme; in its fore-part it's join'd to the fourth and fifth Bone of the Metatarse, behind to the Os Calcis, its inside to the Ossa Cu­neiformia; it lyes on the outside of the Foot, and sustains the little Toes.

The other three are call'd Ossa Cu­neiformia, Ossa Cu­neiformia. or Wedge-like Bones, and lye all in a rank, but differ in bigness one from another, join'd behind to the Os Naviculare, and before to the three first Bones of the Metatarsus: These Bones are Convex outwardly, but hollowish within, for the more safe passage of the Vessels; there's a broad Ligament which passes from the Os Calcis to the Bones of the Metatar­sus, Ligamen­tum Latum. under which the Vessels and Mus­cles lye; for if there were no such, in long standing on the Foot, the action of the Muscles, and circulation of the Juices would have been hindred: It's a sort of Ligamentum Annulare.

The Metatarsus, Metatarsus. or Instep, is com­posed of five long Bones, placed at the [Page 113] side of each other, to sustain each a Toe, very close where they are uni­ted to the Tarsus, but part a little in their middle, to give place to the Mus­culi Interossei; convex outwardly, but hollow within, for the better lying of the Muscles, and passage of the Ves­sels; their lower ends are round, and received into the Cavities of the first Phalanx of the Bones of the Toes by Arthrodia; that which sustains the great Toe the biggest, the next less, and so on to the least of all.

The Bones of the Toes are in num­ber 14, Digiti Pe­dis. for all have three Bones each, except the great Toe, which has only two; their Articulation the same as in the Fingers and the same Observa­tions.

There are sometimes, found in the Articulations of the Fingers, Ossa Sesa­moidea. but espe­cially in the Toes, some very small Bones, call'd Ossa Sesamoidea, Seed-like Bones, because they resemble much the Semina Sesami; they are fastned only by Ligaments in num­ber uncertain, sometimes more, some­times less, in some none at all.

[Page 114] They have the same Use as the Patella. Vse.

The Bones of the Foot being all united together, ☜ may well be compar'd to a Lever plac'd under any great weight, which we intend to raise; for the convex part of the Talus being plac'd just under the Tibia, which, as I have shew'd, sustains the whole Body; the long hinder Process of the Os Calcis, being, as it were, the handle of this Lever, and so rais'd, (as by the Hands) by the Nervus Hectoricus, which is strongly inserted there: This Nerve, or rather Ten­don, is composed of three or four Tendons of several Muscles of the Leg, as Solaris, Gastrochnemii, &c. and with it the whole Body is rais'd, as may be seen when we rear our selves on our Toes.

There's one thing very Curious to ob­serve, N. B. in the bending of the Joints of the Skeleton; for all the Junctures of the Arms, as Elbow, Wrist, and Fingers, bend upwards, but otherwise in the Legs; for at the Thigh it bends forwards, that we may sit when weary; at the Ham back­wards, at the Ankle forwards again, and the Toes backwards: All these several bendings give us a greater strength, both to walk, and rise when down, which we could not do, if the bendings were other­wise disposed.