Book One -- The things that sustain and support the entire body, and what braces and attaches them all. [the bones and the ligaments that interconnect them]

Chapter 18 On the Sacral Bone and the Coccyx

[Figures of Chapter 18]


Key to the three figures placed above and their characters
This table shows the entire structure of the dorsal bones which lie beneath the lumbar vertebrae [os sacrum et os coccygis]. The first figure, on the right, 1 shows the anterior aspect [facies pelvica] of these bones. The second, standing on the left [sic] side, shows the posterior aspect represented slightly from the side to show the depression into which the right iliac bone is articulated. The third figure, in the middle, presents the coccyx in the size and shape usually observed in persons of prime years. 2

A, B, C, D, E, F, G, H, I, K These letters in the first figure denote the nine 3 bones that come after the fifth lumbar vertebra, of which I will consider the six upper [vertebrae sacrales] 4 the sacrum in man; the four lower [vertebrae coccygeae] (G, H, I, K in the third figure) will be called the coccyx, or (as we sometimes say) the coccyx bone.
L, L, R In the first figure, the transverse processes [pars lateralis] of the bones making up the sacrum. Here, L and L


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separately mark the breadth of the process of the second bone, while R both here and in the second figure shows the tubercle of the transverse process of the fifth bone, to which you will hear several ligaments [l. sacro-iliaca, l. sacrotuberale] are attached. In the second figure, L, M, N, R mark the transverse processes of the bones of the sacrum.
N N, O O, and finally P Q F These mark the right depression [pars lateralis, facies auricularis et tuberositas sacralis] of the sacrum in the second figure, to which is connected the right ilium or (as perhaps some will prefer) the iliac bone, 5 and which later is subdivided into several depressions and protuberances. N and N mark its long anterior depression, O and O [crista sacralis lateralis] the tubercle standing out like a broad line, separating the anterior depression [facies auricularis] marked N, N from the posterior depression, marked P, F, and Q. P marks the upper cavity of the posterior depression, Q the lower, F the tubercle [tuberositas sacralis] separating the upper depression marked P from the lower one marked Q.
S In the first and second figure, S marks the right ascending process [crista processus articularis superioris] of the first bone.
T, V, X These letters appear only in the second figure. T marks the depression of the ascending process [p. articularis superior] marked S to which is articulated the tubercle 6 of the right descending process of the fifth lumbar vertebra. V and X mark the anterior and posterior brow of this depression; we have also labeled as X the inner brow of the left ascending process in the second figure.
Y In the second figure is shown the joint [articulatio zygapophysialis] that often appears by which the descending processes of the first sacral bone are joined to the ascending processes of the second, in the same fashion as you learned much earlier the lumbar vertebrae are articulated at this point.
Z In the first and second figures, the joint 7 of the transverse process of the first bone with the transverse process of the second.
a In the first and second figure, the lower, protuberant part [apex ossis sacri] of the sixth bone, which is articulated with the first bone of the coccyx.
b b In all three figures, the cartilaginous ligament [discus intervertebralis] 8 that comes between the joints of the coccyx.
c In the second and third figures, the cartilage attached to the tip of the coccyx.
d d In the second figure are shown the spines or posterior processes of the sacral bones.
e, f, g, h, i, k These letters are somewhat hidden in the second figure, marking the path [canalis sacralis] of the dorsal medulla in the sacrum and the foramina sometimes visible here among the intervals of the spines.
1, 2, 3, 4, 5, 6 These numbers in the first and second figures show the foramina [ff. sacralia anteriora et posteriora] of the nerves [rami posteriores et anteriores] beginning from the dorsal medulla contained in the sacrum; these constitute six pairs, 9 exiting in the anterior and posterior of the sacrum. The first of these [nervus lumbaris V] exits between the first bone of the sacrum and the fifth lumbar vertebra [foramen intervertebrale], and its location is marked 1. The foramen of the second pair, between the first and second bone, is marked 2, and so the rest are shown with their own numbers.

Fourth Figure Fifth Figure

Because in the present chapter mention is made for Galen’s sake of the sacrum and coccyx in apes and dogs, we considered it not irrelevant to represent here those bones [vertebrae] as seen in simians. The fourth figure illustrates the anterior of the sacrum [facies pelvica] and coccyx, the fifth the posterior [facies dorsalis] of the same bones. The numbers 1, 2, 3, etc. mark the six bones, to the third 10 of which a cartilage is separately attached underneath. There is no need for me to depict these bones with additional characters, as they may readily be understood from the human bones.


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11

The anatomical negligence and ignorance of physicians
Just as many facts already mentioned, and others to be enumerated often in this and subsequent books, attest the negligence of doctors who succeeded Galen and their outright gross ignorance in dissections, so assuredly to no lesser degree does a description of the sacrum and coccyx, which everyone will understand. For why, I pray, should we not say those anatomists are rough and untrained who have passed on to posterity Galenic descriptions that are false in some respects and in most cases apply to apes and dogs but not humans, as if they had observed them in man, and were in no way afraid, like scribes, to enumerate things they never saw even in a dream, and often misunderstood in Galen’s books? Where, I ask, after the times of Galen, is mention made of the sacrum and coccyx other than what is passed down by a Galen who is inconsistent in various places? Yet none altogether fits the picture of human bone. For the present, let us dismiss the remaining Galenists, who have obstructed rather than aided the understanding of human anatomy, and reconsider at greater depth the opinion of Galen, who is easily the leader of all professors of anatomy, lest we seem discreditably to have neglected his authority as well.

Galen’s opinion about the sacrum and coccyx
In De usu partium, the sacrum is mentioned more than once. It is said there to be constructed of four bones, but not a syllable is devoted to the coccyx. 12 And besides the fact that Galen does not mention the coccyx there, it is abundantly clear that it was unknown to him when he wrote that book. For while explaining that there are four bones of the sacrum, he adds that a cartilage (c in figs. 2 and 3) is attached to their end, which we shall state in the course of our account grows upon the point of the coccyx; 13 the ends of bones that are not attached to another bone almost always revert into this cartilage. Moreover, in the twelfth book of De usu partium, he asserts that the transverse processes of the sacrum [pars lateralis] (L, L, R in fig. 1 and 2) are thin and delicate, while in De ossibus he teaches that they are thick and broad (as indeed they are). 14 But in his book De ossibus, which he wrote after De usu partium when he had become more skilled in the dissection of monkeys, Galen reckons that the sacrum is formed of three bones (nos. 1, 2, 3 in fig. 4); 15 brief as that book’s description of the bone is, it elegantly and perfectly fits the sacrum of monkeys and dogs. He then enumerates three other ossicles (nos. 4, 5, 6 in fig. 4) beneath the three bones of the sacrum, collectivly called by him the coccyx and briefly described as they are in monkeys. 16 In De anatomicis administrationibus, which he wrote last of all his books of anatomy, as always he deals more with the construction of the ape than of man; thus he mentions the sacrum and the coccyx in such a way that his account does not differ at all from that in De ossibus. 17 When he counts among the muscles that move the femur the one that he says originates from the coccyx (F in the 11th table of muscles), 18 it is quite readily deduced that he is referring to the three ossicles [vertebrae coccygeae I-III] that come in apes below the third bone of the sacrum. 19 Yet in De usu partium, (where he depends to a great degree upon the views of other anatomists) he wrote that this muscle originates from the sacrum (as you will hear happens also in man). 20 So that you may more easily follow the doctrines of Galen and likewise judge the negligence of those who will foolishly copy things they have never seen from the books of others, I shall be glad now to describe both the sacrum and the coccyx as they are in apes and dogs, and afterward begin my account of human bones.

Description of the simian and canine sacrum
In dogs and apes, a certain bone [os sacrum] composed of three bones [vertebrae] is located beneath the lowest lumbar vertebra (nos. 1, 2, 3 in fig. 4; I have placed no further markings on this figure because the human bone is fully marked and it will be explicated later). These are so joined that in front [facies pelvica] near their middle they show the same kind of joint as the bodies of vertebrae would display when fitted together, if they ever came together in such a way that they could not be moved even a little, and all cartilage had disappeared from between them over the passage of time 21 —though in puppies even the union of sacral bones is seen to be filled with a certain amount of cartilage (as in the connection of the epiphyses). In the sides of the anterior place just mentioned, these bones show hardly any appearance of a joint when the animals are old, but appear to have been solid from the beginning, just as the posterior side of these very bones seems quite solid (except perhaps in very young puppies). These three bones joined in this fashion are called the sacrum or large, wide bone by Galen in De ossibus and De anatomicis administrationibus. 22 These bones are laterally broad and continuous, and while they somewhat resemble vertebrae, they form here large, wide transverse processes which join together and have cut into them a conspicuous, uneven, and rough depression [facies auricularis] on their outer side (fig. 5 shows this on each side) by which the ilium is quite firmly attached to the bones. In the posterior part, this bone forms three slender spines [crista sacralis mediana], less upwardly inclined than Galen thought, and constituted throughout like a continuous line. Above and below, this sacrum corresponds to a large degree to the lumbar vertebrae: the upper part resembles their superior surface and the lower resembles the inferior. The upper part of the sacrum [basis ossis sacri] has an epiphysis [processus articularis superior] and protrudes with the same mass as the lower part of the body of the lowest lumbar vertebra [processus articularis inferior], which is joined to the sacrum in exactly the same way as the lumbar vertebrae are joined together. In addition,


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the upper part of the sacrum puts forth two ascending processes, having depressions like the ones with which we stated the ascending processes of the lumbar vertebrae are engraved. The tubercles of the descending processes of the lowest lumbar vertebra are received by these. In addition, the inferior part of the sacrum (which is the lower surface of the third and narrowest of the three bones of the sacrum) also protrudes with a rounded body [cornu sacrale?] quite similar in shape to the bodies of the lumbar vertebrae. It differs from these in no way except that the body of the sacrum is as much smaller than the bodies of the lumbar vertebrae as its body’s mass is smaller than theirs. This body of the sacrum is joined to a single ossicle [vertebra] (no. 4 in fig. four) which will now be described first of the three bones of the coccyx.

Description of the canine coccyx
Beneath the sacrum which is composed of three bones in the manner described, three other ossicles 23 (nos. 4, 5, 6 in fig. 4; compare these with the lumbar vertebrae in the skeletal figures) are assembled one after the other, not unlike the lumbar vertebrae in makeup. In no appearance do they differ from those, except that they have wider transverse processes [cornu coccygeum] than the lumbar vertebrae, slanting downward more than upward, and they put forth no spine or a very small one. In the shape of their body they closely correspond to the lumbar vertebrae, unless perhaps someone considering each detail might add that these ossicles are wider in proportion to their mass. In the ascending and descending processes they do not differ in the least. The topmost of these three ossicles has its body attached to the third bone of the sacrum in the same way as the lumbar vertebrae are interconnected, as it receives the descending processes of the sacrum with its ascending processes. It is no doubt these three lower ossicles that Galen calls the coccyx, for between these three ossicles and between their topmost part and the bottom of the sacrum no less cartilage [discus intervertebralis] or rather cartilaginous ligament may be seen than between the lumbar vertebrae, while as we have just now said no cartilage is seen between the three bones of the sacrum, especially in older animals. In dogs and apes the fourth of the muscles [m. piriformis] that move the femur originates from those three bones: that is the muscle that Galen says originates from the coccyx in the third book 24 of De anatomicis administrationibus. In fact, the foramina [ff. sacralia anteriora et posteriora] 25 incised to transmit nerves agree precisely with Galen’s description in De ossibus: three pairs of nerves are attributed by Galen to the sacrum and three to the coccyx. 26 Among the ancient professors of anatomy the customary way of counting nerve pairs was to have a pair of nerves refer always to the vertebra beneath the nerves (these may be found more or less in order in figs. 2 and 3 at the beginning of ch. 11, Bk. 4). Accordingly they would number the first pair of spinal nerves [n. cervicalis I] the one that exits between the occipital bone and the first neck vertebra; the second pair [n. cervicalis II] was the one for which a path is carved between the first and second neck vertebrae. Thus the first pair of nerves of the sacrum [n. sacralis I] is considered the one which comes out between its first bone and the lowest lumbar vertebra, for which foramina are incised in the way already stated they exist in the lumbar vertebrae. The second and third pair do not exit from the sides like the first. Since the sides of the sacrum are blocked by its articulation with the bones of the pelvis, it was impossible for the nerves to come out through the sides here as well. Consequently foramina are carved in the front and back of the sacrum so that by this provision of Nature branches from these pairs [nervi sacrales, rami posteriores et anteriores] may be directed forward and backward as needed, as they are from nearly all the other pairs. Foramina are also cut out for the second pair at the joint of the first bone with the second, and a way is prepared for the third where the second bone of the sacrum joins the third. For the three pairs of nerves sprouting from the coccyx [nervi coccyges], foramina [f. intervertebrale] are carved exactly as they are in the lumbar vertebrae; for since the sides of these bones are not (like those of the sacrum) occupied by a joint [articulationes zygapophysiales], it was more fitting to maintain here the same series of foramina as we have explained exists in the other vertebrae not blocked by a lateral articulation, particularly since the articulation of these ossicles is identical to that by which the lumbar vertebrae are joined together. Thus the first pair [nervus coccygeus, plexus coccygeus] comes forth on either side through a foramen cut between the third bone of the sacrum and the first of the coccyx, the second pair [nervus ano-coccygeus] between the first and second of the coccyx, and the third pair [n. ano-coccygeus] between the second and third. From the lower side of the third bone, what is left of the dorsal medulla [filum terminale] comes forth without a partner and allied with nothing. A path [foramen intervertebrale] is carved for the dorsal medulla in each bone of the sacrum and the coccyx, corresponding to the thickness of the medulla at this point. At the end of the third coccyx bone in dogs and caudate apes, solid and unperforated bones, oblong and somewhat thick above and below but thin in the middle, are connected in a more or less continuous series constituting the tail [vertebrae caudales]. 27 Sometimes, not infrequently, in many species of dogs and apes even more than three coccyx bones are seen, of exactly the same shape as those above, and in them still more nerve pairs come out from their sides. In tailless apes, only cartilage grows upon the lowest bone of the coccyx, though Galen’s opinion is not as readily understood regarding these as regarding dogs. Since this is the case in those animals and because I understand Galen’s description best from them and quite cheerfully give them equal attention when performing demonstrations in the schools and subsequently


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find them altogether different in man, why, I ask, do certain dilettantes and those who swear by Galen’s words, born for no other purpose than to detract and make invidious judgements of others’ labors (since they can do nothing themselves), now rail against me because I so often disagree with the opinions of Galen during dissections? It is as if they had no eyes, and because of some Galenic religion it were not permitted me to present, often to the most learned men of my time, what I find by myself. In the meantime, no spirit good or evil can silence these ranters if they have discovered something they think worthy of the subject of medicine: whether medicine is a craft or a science; whether a discussion of categories is logical or metaphysical in character; about the possibility of understanding; whether knowledge about the soul is the highest form of knowledge, and other foolishness. 28 But in no way do I pay attention to those laughable but arrogant men, as it has been my longstanding habit to ignore them; I expect thanks rather from those who are zealous for truth, for although I repeatedly mention the views of Galen, I myself study the true construction of man, even if perhaps my language digresses too far. Nor do I believe the ghost of Galen (who is seen so often to have lamented in his writings that the study of anatomy would perish utterly with him, as indeed was the case) will be unfriendly to me because I am showing that he taught the fabric of the ape rather than man and on account of the books of other anatomists who preceded him he proceded from the construction of the ape to that of man and confused the two. I do not say this because Galen mixed human bones with simian in his description of the sacrum and coccyx (unless he knowingly counted a smaller number of coccyx bones than often occur in caudate monkeys), but because he counts only five lumbar vertebrae when dogs and caudate monkeys have more; 29 Galen nevertheless describes the vertebrae, sacrum, and coccyx of a monkey. That the ancients conscientiously employed human bones while training their sons in anatomy, 30 is attested by names taken from the parts themselves. I am certain they called a certain bone ko/kkuc from some similarity that it has with a bird also called coccyx by Pliny (and by us cuculus, cuckoo), especially when it has not been completely cleaned of flesh and ligaments. 31 What this resemblance could be, I shall more readily explain after I have appended a brief description of these bones in man.

Description of the human sacrum
Beneath the lumbar vertebrae in man ten bones are generally found (G, H, I, K in the fig. in ch. 14, M and N in the skeletal figures, all of figs. 1 and 2 in this ch.), of which six make up the human sacrum 32 and four the coccyx. The six upper bones (A to F in fig. 1) are joined together in the same way it has been related the three bones making up the canine sacrum (1, 2, 3 in fig. 4) are united. In the middle of their anterior surface they display a bond of the sort the bodies of the vertebrae would form (R in the fig. for chapter 14) [discus intervertebralis] if they had joined to the extent that no cartilage were seen in the union of these six bones, 33 except perhaps in very young children whose bones have not yet altogether fused. On the sides of the anterior part, where (so to speak) the transverse processes of these six bones are joined together (L, L, R in figs. 1 and 2) a quite obscure kind of joint appears. On the posterior surface, the union is done away with altogether and a single bone made of those six is observed. No line of a union presents itself here, except sometimes at the meeting of the first bone [vertebra sacralis I] with the second [vertebra sacralis II] (Z in figs. 1 and 2). Often, in fact, the first bone is observed to be joined to the second on its posterior surface by the kind of joint [articulationes zygapophysiales] with which the ascending and descending processes of the lumbar vertebrae are regularly articulated. But although those processes are so joined, the transverse processes of this bone fuse everywhere with those of the second bone, and all such joints are so strong that the first bone is unable to be moved at all upon the second. Sometimes, however, sacra found in cemeteries show the first bone broken away, and it is found separately as if it had been a lumbar vertebra. For were it not that this first bone has thick, broad transverse processes, its shape would be hard to distinguish from that of lumbar vertebrae. In children, the joint of these six bones is conspicuous even on the posterior side and extremely prominent on the anterior. In no humans is the joint wholly invisible on the anterior surface; similarly, on the posterior surface of the sacrum the kind of joint always presents itself which is fashioned by the bodies of the bones. For if you examine the foramen [canalis sacralis] incised in the sacrum for the dorsal medulla (f, g, h, i, k in fig. 2), 34 you will see that the bodies of the bones have fused through the course of the foramen as clearly as on the anterior surface. This set of six bones corresponds to the three bones which make up the sacrum of the dog; for just as in the dog the topmost bone is greater than the middle and the middle greater than the lowest, so in man the bones are smaller the lower their position on the sacrum. The second bone, however, is exceptional in that its transverse processes are broader and thicker, and more prominent anteriorly and posteriorly (from Z to slightly below the lower L in fig. 1) than the other bones of the sacrum. 35 The upper part of the first or topmost bone [vertebra sacralis I] (compare the upper part in figs. 1 and 2 with the figs. in ch. 17, or see the joint in the skeletons and the fig. in ch. 14) corresponds in every way to the superior surface of any lumbar vertebra. And the body of the fifth lumbar vertebra is fitted to the first bone of the sacrum in the same way that the lumbar vertebrae receive the tubercles of the processes [processus articularis inferior vertebrae lumbalis] of the vertebra above. The lower part of the sixth bone (a in fig. 1) differs significantly from the inferior surface of the third canine [sacral] bone: the human bone possesses no descending


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processes by which to articulate with a bone beneath it. Instead, it ends in a circular but slightly broader tubercle [apex ossis sacri], which in humans is attached to the first bone of the coccyx in the same fashion as the bodies of the vertebrae (R in the fig. for ch. 14, or b in figs. 1, 2, 3 of this ch.) 36 are articulated with each other, or better yet the bones of the tail [os coccygis]. Moreover, a depression [facies auricularis] (N, N, etc. in fig. 2) is carved out in the transverse processes [pars lateralis] of the human sacrum, on the outside slightly towards the posterior, to which on each side the iliac bone (A, B, C, etc. in fig. 3, ch. 29) [facies sacropelvica, f. auricularis] is very strongly attached. This depression is quite rough and uneven, and has in the middle along its longitude a projecting line (O, O in fig. 2) or tubercle standing out like a rather wide line, which in turn separates the depression into anterior and posterior depressions. The anterior one [facies auricularis] (N, N in fig. 2) is quite simple but rough, and rather unevenly incised; the posterior (P, Q, F in fig. 2; P and Q mark the two depressions, F the swelling [tuberositas sacralis]) is more deeply hollowed, but shows in its middle a process that swells transversely and subdivides the posterior depression into upper and lower parts. The ilia [facies auricularis ossis ilii] correspond exactly to these depressions, being equipped with matching protrusions and depressions. These cavities and swellings are not covered with cartilage like the other cavities. For although other swellings and depressions are coated with smooth, continuous, and flat cartilage, these depressions of the sacrum produce nothing but cartilaginous ligaments [ll. sacro-iliaca interossea] connecting the sacrum very tightly to the ilium. These depressions are particularly associated with the three upper bones of the sacrum, for the lower bones have slender, broad, and blended transverse processes from which originates the muscle [m. piriformis] (F in the 11th table of muscles) that will be considered the fourth muscle of femoral movements. The transverse process of the fifth sacral bone, however, puts forth a tubercle (R in figures 1 and 2) at the point where it merges with the process of the sixth bone; this tubercle is quite prominent and thick, formed so that two ligaments (g and d in the 10th table of muscles) may conveniently be inserted in the sacrum, 37 one of which will be shown to originate from the acute process of the hip (d in fig. 2, ch. 29 [spina ischiadica]), the other from the upper part of the appendix which you will hear the hip has (l in the same fig.) [tuber ischiadicum].

Foramina transmitting nerves in the sacrum
The foramina carved out in these six bones to carry nerves [nervi sacrales] (1-6 in figs. 1 and 2; better yet, see figs. 2 and 3 at the head of ch. 11, Bk. 4) in every way resemble in appearance, if not in number, those cut in the three canine bones [vertebrae sacrales I-III]. In the human, five are cut on each side of the anterior surface next to the joint of the bodies, and the same number in the posterior, so that these bones provide a path [foramen sacrale] for six pairs of nerves. The first pair [nervus lumbalis V, rami posteriores et anteriores] exits between the first sacral bone and the fifth lumbar vertebra, in the same way as the other nerves proceeding from the sides of the lumbar and thoracic vertebrae. The second pair [nervus sacralis II, rami posteriores et anteriores] exits between the first and second sacral bones; the others in this series come out in succession so that the emerging pair always takes its number from the bone beneath. Besides these foramina carved out for the nerves, others (e-k in fig. 2) appear in the posterior side of the sacrum between the spines of the bones, facing into the route [canalis sacralis] prepared for the dorsal medulla. 38 These foramina are filled with ligaments, just like the intervals and foramina visible between the spines of the other vertebrae.

Spines of the sacrum
These intervals between the spines of the sacrum (d, d, d in fig. 2) sometimes appear continuous and uninterrupted [crista sacralis mediana] by any foramina, almost as in dogs. But in fact the bones of the sacrum do have spines, taller as the bones from which they grow are higher and larger. But no spine (so far as I can judge) angles the least bit upward: they all face downward, and as in the other vertebrae they create a certain interval [facies dorsalis] with the transverse processes, a place where several muscles [m. erector spinae] that move the back (10th table of muscles, and in subsequent tables as far as 14 in this part of the back) are appropriately located, and whence they best originate with other muscles 39 that go forth from this point.

The nature of the anterior and posterior areas of the sacrum
The entire posterior of the sacrum is convex and curved so as more safely to protect as a bulwark the parts which it shelters and to guard them from impacts. On the anterior is it smooth, not rough, but flat and concave, the better to form a place for those organs which it encloses together with the other bones [ossa coxae] like a kind of basin. 40 This is how the human sacrum is arranged, sometimes made up of only five bones, in which case two foramina are missing in the anterior; but in the posterior a path is always seen for six pairs of nerves [segmenta medullae spinalis, pars sacralis].

An account of the coccyx
The coccyx (G, H, I, K in figs. 1 and 3; I, K in the fig. for ch. 14, N in the skeletons) is constructed of four ossicles, the topmost of which forms a depression in which is received the tubercle [apex ossis sacri] of the sixth sacral bone (F in fig. 1), which is attached to it in the manner of vertebral bodies by a quite cartilaginous ligament [discus intervertebralis], but without any other kind of articulation, save in cases where the sacrum is made of only five bones. To provide in such cases for the construction of a foramen in the posterior side, and to bring down and protect a nerve of the sixth sacral pair, this first bone puts out in its posterior side two small, sharp processes [cornu coccygeum] which face upward and form a strong bond with the processes of the fifth sacral bone. The first ossicle of the coccyx itself is joined with the fifth sacral bone scarcely at all by cartilaginous ligament, but virtually fuses with it like the bones of the sacrum. When there are six bones in the sacrum (which happens most often), 41 the first bone of the coccyx puts forth no such processes. 42 At the sides of the depression by which it is joined to the sixth bone of the sacrum, it widens transversely [processus transversus] in its upper portion but narrows gradually in its lower portion, and in turn is joined to the second bone (lower b [discus intervertebralis] in fig. 2) exactly as we said it is joined to the sixth bone of the sacrum. The third and fourth bones follow, attached to each other in quite the same manner, and as much smaller the lower the place in the series each takes. No foramen [canalis centralis] is ever carved


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in these ossicles for the dorsal medulla to continue its course, or for any nerves to go out. The spinal medulla terminates in the sixth bone of the sacrum, and its end (56 in figs. 2, 3, ch. 11, Bk. 4) [filum terminale] does not go down into the coccyx. These ossicles are spongy, reddish like the breastbone [sternum], and in children quite cartilaginous. They taper overall from a rather broad base to a point and are curved inward like the beak of a cuckoo. The lowest ossicle reverts into cartilage at its point (c in figures 2 and 3), where it touches the rear and lowest point of the straight intestine (a in fig. 8, Bk. 5) [rectum], for the same purpose that we have stated cartilage grows on the spines of the vertebrae.

Those who contend Galen taught human anatomy are disrespectful toward him.
It is surely clear from this how disrespectful we should be toward Galen if we argued that he gave an account of the human fabric and did not ever admit that he was concerned rather with the construction of apes, and then if we did not believe Galen himself at the beginning of the third book of his Notes on Hippocrates’ Book De Articulis when he says he had written his book De ossibus after he had seen exactly what each bone was like: chiefly in the dried-up cadavers of actual humans, and if not there then he had certainly inspected them carefully in monkeys — so indicating that he had made every effort to describe monkeys, at least, and that they are very similar to man in the construction of their bones. 43 If anyone should wish to force Galen’s account upon the structure of humans and not monkeys, he will agree that Galen missed the four bones (G-K in figs. 1 and 3) which we have counted as the coccyx. He will also falsely charge Galen with ignorance of six foramina (4, 5, 6 in fig. 1), since in man there are six foramina on each side in the anterior surface of the sacrum, while in dogs only three occur. 44 The foramina visible in the coccyx of dogs are only in the posterior side, or rather they are located in the sides, as Galen also quite truthfully recounts while making no mention of anterior foramina. In addition, we should be compelled unbecomingly to charge Galen with negligence for stating that the structure of the three lower bones of the human sacrum is not the same as that in the three upper, for no more cartilage intervenes in the union of the lower bones than in the upper. But at the same time, no amount of cartilaginous ligament joins the ossicles of the human coccyx: Galen believed the substance was cartilage, as in the bodies of the vertebrae. So, should we press each of our inquiries harder, we would still concede willy-nilly that Galen had falsified the true descriptions of other anatomists.

The reason for the name of the coccyx and sacrum
No one should doubt that these four human ossicles had been called ko/kkuc by the ancients from their obliquity of shape, their pointed outline, and their red color, because the ancients compared all these features to the beak of a cuckoo for the benefit of their sons. 45 Yet there is no similarity between these bones in dogs and humans. The features which fit Galen's description apply to the lumbar vertebrae in every point of resemblance, as we have stated. They called the sacrum platu/, or wide and broad, because its breadth easily exceeds that of the other vertebrae, beneath which it is placed as a basis and very safe foundation. 46 I do not believe they compared it in breadth with all the bones, since the iliac bones are known to be broader than the sacrum. It is unclear why they called it i(ero/n or sacred, unless they called it so from its rare appearance and shape, or because it so resembles a divine bulwark, or because many people think (falesly) that by divine aid, without the aid of muscles, the connections 47 of this bone with the ilium are opened during childbirth, and joined again by natural instinct; or because it is grand and spacious, as we think Troy, the sea, hunger, and such like are called “sacred” by the poets. 48 But as we have said regarding its breadth, the sacrum would need to be compared only with the vertebrae, since the bones attached to it on each side, as well as the femur and the tibia, are larger than the sacrum. Moreover, these consist only (if I may say so) of a single bone, while the sacrum is a combination of six. Others investigating the reason for this name cite one thing or another about the sacrifices of the ancients. Since I am everywhere quite happy to leave to others the reason for names, I shall gladly withdraw from the investigation of this name.

The 1555 Version of Chapter XVIII

The ten bones to be described in this chapter
Beneath the lumbar vertebrae (E, F in the fig. for ch. 14) are situated ten bones [os sacrum, os coccygis] (G-K in the same fig., M, N in the skeletons, and all of figs. 1, 2 in this chapter), of which the remaining part of the backbone, extending from the loins to the anus, is made up. The upper six of these [vertebrae sacrales] (nos. 25-30 in the fig. for ch. 14, A-F in fig. 1 of this chapter) are so attached to each other that when they are unearthed from graves they are usually all together, almost like a single bone. 49

The sacrum or wide bone
We see this called platu/ by the Greeks and latum or amplum by the Latins because its width, especially in man, in whom it is proportionally wider than in other animals (as is the backbone as a whole) easily surpasses the breadth of the other vertebrae on its upper side, being placed beneath them like a foundation and an extremely sound fulcrum. 50 I do not believe the ancients compared this in breadth with all the bones of the body, since the iliac bones (the widest portions of the figures in ch. 29; o in the skeletons) are far wider. Why they called this the i(ero/n or sacrum is unclear to me, unless it happened as a result of its uncommon look and shape, or because it so resembles a strange bulwark, in various ways fending off anything that faces it even in a cursory way as it rests upon its base; or because it was believed (wrongly) by many that during childbirth its connections [ligg. sacro-iliaca] with the iliac bones are relaxed, open up, and then come together miraculously, without the aid of muscles; 51 or perhaps because it appears large and great, in the same way as in the poets, I believe, Troy, the sea, hunger, and other things are called “sacred.” 52 But even so (once its breadth has been mentioned) the sacral bone should be compared only to the vertebrae, since the bones attached to it on each side, the femora (L in the skeletons), and the inner bones of the tibiae (F in the skeletons) are greater than it is, though composed of a single bone while the sacrum is a combination of six. Others, carefully investigating the reason for this name, contrive something or another about the sacrifices of the ancients. Many apply other names to this bone, which will be added to the end of this book along with all the nomenclature of other bones to avoid confusing the text unnecessarily here and elsewhere with inept and barbaric words.

The coccyx
The four ossicles [vertebrae coccygeae] 53 (31-34 in the fig. for ch. 14, G-K in figs. 1, 3 of this chapter) which come after the sacrum are named after the shape of a cuckoo bird’s beak and (as it were) its color, 54 just as if they were a single bone, chiefly called ko/kkuc by the Greeks and the Latins as well, as it will now be known more intelligibly in our entire account of these ten bones.

Description of the sacrum; the connection of its bones
The six upper bones, forming the sacrum, are so mutually constructed that they show the same connection (A-F in the middle of fig. 1) in the middle of their anterior surface [facies pelvica] as the vertebral bodies would have put forth had they so far fused that nothing more of the cartilaginous ligament [discus intervertebralis] (R in the fig. for ch. 14) were seen between them. In children, however, where these bones have not yet fully or as strongly grown together as in persons of advanced years, some cartilage occurs in this union just as it does in their epiphyseal unions. In the sides of the anterior surface, where the so-called transverse processes [pars lateralis] of these six bones (they are no less wide than the bodies of the bones) are fused to each other, the type of connection 55 is still more obscure than in the middle. But in the posterior side (fig. 2) the union is altogether missing, and it looks like a single bone formed from the six. No line of union presents itself here, except sometimes in the meeting of the first bone with the second, for the first bone is occasionally joined with the second [articulatio zygapophysialis] (Y in fig. 2) by the kind of joint by which the ascending and descending processes [proc. articularis superior et inferior] of the lumbar vertebrae (the lowest O and N in the fig. for ch. 14) are articulated. But although those processes of the sacrum are joined in that way, the transverse processes of the first bone fuse everywhere (Z in fig. 2) with those of the second bone; all these connections are so strong that the first bone cannot be moved even the least bit on the second. I do not once recall finding a sacrum in the cemeteries where the first bone had been broken off and which was discovered apart almost as if it were a lumbar vertebra (figs. in ch. 17). Were that first bone not equipped with thick, wide processes, its form could scarcely be distinguished from that of lumbar vertebrae. In children, the meeting of these six bones is visible even on the posterior side, just as we have said it is clearly manifest on the anterior of their sacrum as well. As in no persons is the type and place of fusion 56 altogether and completely erased in the middle of the anterior side, so also in the posterior side of the sacrum an image forever presents itself of the fusion which happened to the bodies of the bones.

The foramen made for the dorsal medulla
For if you pay attention to the foramen [canalis sacralis] (e-k in fig. 2) incised for the dorsal medulla [m. spinalis] in all the bones of the sacrum, you will perceive through the course of the foramen as clearly as on the anterior side that the bodies of the bones are joined there. The entire series of bones (figs. 1, 2) running downward from a broad base [basis ossis sacri] to a point [apex ossis sacri] is of such a kind that each bone becomes smaller the lower its position in the sacrum and in the series itself. This notwithstanding, the second bone [vertebra sacralis II] (B in fig. 1) is constructed with wider, thicker, and more forward and backwardly prominent transverse processes [partes laterales] (L, L in figs. 1, 2) than the other bones of the sacrum.

The upper surface of the sacrum
The upper part [basis ossis sacri] (top of figs. 1, 2) of the first or highest bone corresponds in shape to the upper surface [corpus vertebrae, facies intervertebralis] of any lumbar vertebra (upper surface in figs. 1 & 2, ch. 17). In its middle it protrudes with a round body [promontorium] (above A, fig. 1) having an epiphysis, in amplitude matching the lower side of the body of the fifth lumbar vertebra. It is attached to that vertebra (F is joined to G in the fig. for ch. 14) in the same way that we see the bodies of the lumbar vertebrae are attached to each other by a thick cartilaginous ligament [discus intervertebralis]. // p. 101 // The posterior side of the first bone puts forth two ascending processes [pp. articulares superiores] (S, T, V, X in figs. 1, 2) carved out in the same way as the ascending processes of the vertebrae in the loins [pp. articulares superiores] (K in figs. 2, 3, ch. 17). These processes of the sacrum admit the descending processes [pp. articulares inferiores] of the five lumbar vertebrae in quite the same way as the lumbar vertebrae are joined to each other by the same such processes.

The lower surface
The lower part of the sixth bone [apex ossis sacri] (a in figs. 1, 2), rather slender as the bone itself is slight, has no descending processes with which to articulate with the bone beneath it. Instead, it ends only in a round but slightly widened tubercle or body which is connected to the first ossicle of the coccyx [vertebra coccygea I] (G in figs. 1, 3) by no other means than the vertebral bodies are bound to each other, by a wide and cartilaginous ligament [discus intervertebralis].

The sides
A depression [pars lateralis, facies auricularis et tuberositas sacralis] (N, O, O, P, Q, F in fig. 2) is carved in the transverse processes of the sacral bones in their outer side somewhat toward the posterior, to which the iliac bone (what is above S, N, C in fig. 3, ch. 29) is very strongly fitted on either side. This depression is quite rough and irregular. First, it has a line [crista sacralis lateralis] (O, O in fig. 2), or a tubercle that stands out like a rather wide line, projecting through its length in the middle. This divides the depression in turn into an anterior depression [facies auricularis] (N, N in fig. 2) and a posterior depression (P, F, Q in fig. 2). The anterior is quite simple but rough, and is quite irregularly incised. The posterior is more deeply hollowed, but in the middle it shows a process [tuberositas sacralis] (F in fig. 2) projecting transversely, which divides this posterior depression into an upper (P in fig. 2) and a lower (Q in fig. 2) depression. The iliac bones fit these depressions and projections, having corresponding projections and depressions [facies sacropelvica] (A-G in fig. 3, ch. 29). But these high and low places are not covered with smooth, slippery cartilage like other sockets and heads made for articulation: they put forth nothing but cartilaginous ligaments which bind the sacrum in the most robust way to the iliac bones without a slippery, smooth juncture almost as the epiphyses are attached to their bones. 57 These depressions, carved in the transverse processes of the sacrum and made rough by blind foramina so as to put forth ligaments, 58 are most particularly typical of the three upper bones of the sacrum. The lower bones have thin but wide processes that run together, from which a muscle originates (F in the 11th table of muscles) [m. piriformis] which we shall establish as the fourth of the muscles that move the femur. But at the point where it is joined to the transverse process of the sixth, the transverse process of the fifth bone puts forth a quite thick, prominent tubercle (R in figs. 1, 2) so that two ligaments (g and d in the 10th table of muscles) 59 may be implanted here in the sacrum. One of these, it will be explained, originates from the sharp process of the hipbone [spina ischiadica] (d in fig. 2, ch. 29), the other from the upper posterior surface (l in the same figure) [tuber ischiadicum] of the epiphysis which you will learn belongs to the hipbone [os ischii].

The posterior side
The spines or posterior processes [crista sacralis mediana] (d, d, d in fig. 2) also occur in the bones of the sacrum, the higher on each bone as the bone itself from which it grows is larger and higher. But the sixth bone and generally the fifth, at the place (i, k in fig. 2) where the others put forth the spine and to which the end [filum terminale] of the dorsal medulla extends, develop a gap [canalis sacralis], are open in various ways — not the same way for all — and lack spines. Whatever the case, no spine of the sacrum, if I understand anything correctly, angles in the least degree upward: rather, all face downward, just as in the other vertebrae when they establish an interval for the transverse processes and a place into which several muscles that move the back (G in the 13th table of muscles, T in the 14th) [m. erector spinae] are fitly situated and from which they most properly originate along with other muscles (T of muscle Q in the 10th table of muscles, K of muscle D in the 12th) 60 taking their origin from here. That is why this posterior surface of the sacrum is remarkably rough and as if decayed, clearly so that the beginnings of muscles may be more conveniently brought from them along with ligaments. The whole area is convex and curved so as more safely to serve as a bulwark for the parts which the sacrum contains.

The anterior
On the anterior side it is smooth and wider but not rough; it is depressed and concave so as to form a more fitting surface for those organs which together with the other bones attached to it (Q [os ilii] joined to M [sacrum] in the skeletons) // p. 102 // it surrounds like a kind of basin [Lat. pelvis]. The lowest region of the back, being almost semicircular, does not make a straight line with the coccyx beneath it. 61 Sometimes, not infrequently, the sacrum is made of only five bones, showing in almost all its construction nothing peculiar except in the series of foramina that transmit its nerves, as I shall state presently.

Foramina provided for the transmittal of nerves
From the portion of the dorsal medulla situated in the sacrum 62 (F, G, 24, 30 in fig. 1, ch. 11, bk. 4) six pairs of nerves [cauda equina] generally sprout; the first of them (25 in fig. 2, ch. 11, bk. 4) 63 comes out between the fifth lumbar vertebra and the first bone of the sacrum in the same way as the nerves come out from the sides of vertebrae in the thorax and the loins. From the back of the body of the first bone and before the anterior surface of this bone’s ascending process [p. articularis superior], a cavity [foramen intervertebrale] (1 in figs. 1, 2) is hollowed out on each side which makes a common foramen with the cavity of the fifth lumbar vertebra, by which a nerve 64 escapes on each side; a vein and an artery 65 also enter here to the dorsal medulla. Foramina are not provided for the remaining pairs of nerves in the sides of the sacrum occupied by the attachment of the iliac bones above, and below where they are transversely so thin that they could not be pierced by too long a lateral course. Therefore when the sacrum is made of six bones (as in all our figures) ten round foramina will be seen in its anterior and posterior surfaces, five on each side (2-6 in figs. 1, 2) [foramina sacralia anteriora et posteriora]; these are carved out between the bones where they come together, and become narrower the lower their position on the sacrum. The nerves (in figs. 2-3, ch. 11, bk. 4) [nervi sacrales] for which they provide a path are therefore not of an equal size above and below. For the same reason, the foramina carved in the posterior side are smaller than those which are seen in the anterior, for on the latter side the nerves are thicker than those which exit on the former and because more and larger veins and arteries enter the sacrum through the anterior foramina than through the posterior. The foramina being as they are, the second pair of nerves [nervus sacralis I] of the sacrum puts forth two branches forward and the same number to the rear [nervi sacrales, rami anteriores et rami posteriores] through the four foramina provided for them between the first bone and the second. The other pairs come forth in such a way that the exiting pair is numbered according to the bone beneath it, as in the vertebrae. Besides these foramina cut for the nerves, others (f, g, h in fig. 2) occur at intervals between the spines of the bones in the posterior side of the sacrum, reaching into the path [hiatus sacralis] where the dorsal medulla is carried and filled with ligaments, just like the intervals and foramina seen between the spines of the other vertebrae.

What happens when the sacrum is made of only five bones
Whenever the sacrum is made of only five bones, 66 two foramina are missing in its anterior side and a path is carved for the sixth pair only in the posterior surface (but more towards the sides); there is also a different type of joint between the lower part of the sacrum and the coccyx. The topmost ossicle of the coccyx has a depression carved in its top surface and it not only receives the body of the fifth sacral bone, but it puts forth two small processes [cornu coccygeum] besides which are brought upward and fuse with small processes [cornu sacrale] of the fifth sacral bone which face downward.

Description of the coccyx
A quite small portion of cartilaginous ligament [discus intervertebralis] has a role in what remains of this attachment, more or less corresponding to the common structure of the sacral bones. But when there are six of them [vertebrae sacrales], the highest ossicle [vertebra coccygea I] (G in figs. 1, 3) of the coccyx raises no little processes [cornu coccygeum] in its posterior side and is only loosely joined to the body of the sixth sacral bone (a in figs. 1, 2) [apex ossis sacri] by means of a cartilaginous ligament [discus intervertebralis] (b in figs. 1, 2). This ossicle is transversely and upwardly convex at both sides 67 of its depression and gradually narrows from here downward. It is supported (b in fig. 3) [discus intervertebralis] by the second ossicle of the coccyx [vertebra coccygea II] (H in figs. 1, 3)in the same way as it is by the sixth sacral bone. The third and fourth ossicles follow the second, joined together in exactly the same way, and narrower and shorter as each occupies the lower position in the series. The fourth ossicle (K in figs. 1, 3) ends with a cartilage (c in fig. 3) where its point touches the final and lowest part [m. sphincter ani externus] (M in fig. 1, ch. 49, bk. 2) of the straight intestine, // p. 103 // for the same purpose that we have said cartilages grow on the spines of the vertebrae and the extremities of other bones. No foramen is cut into these four ossicles for the dorsal medulla to enter or for any nerves to make their exit. The substance of these ossicles resembles that of epiphyses: spongy, porous, and rather cartilaginous in children. Their common structure ends in a point from a broad base and is markedly bent inward in a slanting curve. Because of its loose attachment, it is movable in childbirth and sometimes when the anus is opened widely. Since this structure of the four bones gradually narrows to a point from a kind of base, is curved, and is reddish 68 before it dries, somewhat like the pectoral bone, it is likely that the ancients, who taught boys the art of dissecting bodies, compared its appearance to a cuckoo’s beak, and for this reason called it chiefly ko/kkuc as we stated earlier, and o)rropu/gion 69 because the structure to a great extent resembles the movable ossicles in the tail of birds, but unlike the beginning of the tail of quadrupeds.

How Galen described the sacrum and coccyx
You will readily judge how our account of the sacrum and coccyx agrees with Galen’s descriptions if you compare them first with each other (since they are not consistent) and then with ours. In the books On the Use of the Parts the sacrum is mentioned more than once; 70 it is explained there that it is constructed of four bones, without the least word added about the coccyx. Besides the fact that Galen paid no attention to the coccyx in those books, there can be little doubt that it was unknown to him while he was writing those books and giving a quite inaccurate count of the nerves. For when he states that the bones of the sacrum are four, he adds that a cartilage 71 is attached to their end [apex ossis sacri] like the one that we stated is on the point of the coccyx, and into which the ends of bones not attached to another bone almost always revert. Moreover, in the twelfth book On the Use of the Parts he states that the transverse processes [pars lateralis] of the sacrum are thin and delicate, while in his book On the Bones he explains that they are thick and wide (as indeed they are). 72 In this book he says that the sacrum is formed from only three bones, 73 writing that three other are situated beneath them, to which he gave the name coccyx. Also in his books On Anatomical Procedures he now and again mentions the sacrum and coccyx, as he does sometimes in his Commentary on Hippocrates’ Book ‘On the Joints,’ but he does so (as far as I can understand his opinion) according to exactly the same system that he describes more fully than elsewhere in On the Bones. 74 So that you may the better judge whether the construction of bones described there is simian rather than human, I shall now be glad to explain how the bones situated beneath the lumbar vertebrae occur in monkeys and dogs. This must be done the more attentively, as the impudence of those who maintain that Galen described humans rather than simians is altogether damnable. Such persons daily pervert his books in the most disgraceful way and attribute all sorts of things to copyists and scribes, more and more bringing it about that finally the writings of Galen can be applied to some Chimaera, but not to monkeys or the animals that Galen most dissected, nor to humans. 75

The bone formed from three bones in the ape and the dog, which we call the sacrum
In the ape and the dog, a certain bone (nos. 1-3 in fig. 4; fig. 5 shows the posterior side) is located beneath the lowest lumbar vertebra; it is composed of three bones 76 so joined together that in their anterior side near the middle they display the kind of connection that the bodies of the vertebrae would show if they ever fused in such a way they could not be moved in the slightest way, and all the cartilage between them had disappeared with the passage of time — though in puppies the union of those three bones is still filled with some cartilage, 77 as in the attachment of epiphyses. In the sides of the anterior surface just mentioned, these bones in advanced age show hardly any appearance of fusion; likewise, their posterior surface (except perhaps in quite young puppies) // p. 104 // looks altogether continuous. The first bone has a round body on its upper side no different from that of any lumbar vertebra, 78 joined to the lowest lumbar vertebra in the same way as the lumbar vertebrae are joined to each other. This first bone puts forth ascending processes [p. articularis superior] by which the descending processes of the lowest lumbar vertebra are received [articulatio zygapophysialis]. The lower side of the third bone corresponds to the lower side of any lumbar vertebra in that like them it has a round body and descending processes by which it is articulated to the ossicle beneath it (4 in fig. 4) [os coccygis I] no differently than the lumbar vertebrae are put together. The sides of these three bones, which have quite broad and wide transverse processes continuous with each other, also have a depression [pars lateralis, facies auricularis] carved toward their posterior side, which is rough and uneven and serves for the connection of the iliac bone to these bones on each side. This depression is proportionally shorter than the one in the human sacrum, to the degree that the iliac bone in man is much broader than in quadrupeds. 79 The transverse processes in the second of these bones do not exceed those of the first in size, and the second bone is in every way lesser than the first, as the third is also lesser than the second. In these three bones is carved a continuous foramen [canalis sacralis] through which the dorsal medulla runs, and from their posterior surface they each put forth a spine or posterior process facing upward rather than downward, though not conspicuously so, and as much smaller as is the bone from which it rises in the series. In the intervals between the spines there are no foramina, not do the bones separate at all there; rather, the spines protrude like a single line, more or less continuously with each other. Four foramina provided for the exit of nerves show themselves on the anterior [foramina sacralia anteriora] and posterior [for. sac. posteriora] sides, two on each side, by which a route is supplied to the front and the rear for the branches of the second and third nerve pairs 80 belonging to these bones. The foramen is prepared for the first pair 81 in the same way as in the lumbar vertebrae, at the back of the body of the first bone [vertebra sacralis I] and the lowest lumbar vertebra [vert. lumbalis V].

The ossicles beneath the sacrum in the ape and the dog, and their coccyx
In these animals, the dorsal medulla does not end at the end of the third bone, but proceeds downward through other ossicles [os coccygis] (4-6 in fig. 4; they are also seen in fig. 5) besides, which like the lumbar vertebrae offer a path [foramen intervertebrale] for the nerves to the posterior part of their bodies but not the anterior [ff. sacralia anteriora] where the second and third pairs 82 belonging to the bones of the sacrum put forth their principal branches. The nerves [n. sacralis III ?] coming out beneath the third bone, constituting the first pair of the nerves of the dorsal medulla contained in the ossicles beneath the third bone, have foramina between the third bone [n. sacralis III] and the first ossicle (between 3 and 5 in fig. 4) just as do the nerves exiting from the lumbar vertebrae, from the back of the vertebral bodies. Thus, beneath the third bone of the sacrum three other ossicles follow [vertebrae coccygeae I-III] (4-6 in fig. 4), and sometimes more in caudate apes and some dogs, 83 extremely similar in shape to lumbar vertebrae. In no appearance do they differ, except they have wider transverse processes [pares laterales] than lumbar vertebrae and they slope more downward than upward; they also put forth no spine or a very small one. In the shape of their body they closely resemble those vertebrae, though someone looking at the smallest might add that they are wider in proportion to their size. In the ascending and descending processes, however, they are not at all different. The highest of them 84 is connected to the lowest part of the sacrum, and they are with each other, by the same articulation or attachment as the lumbar vertebrae. Thus in the connection of their bodies as well there occurs a noteworthy portion of cartilage or rather of cartilaginous ligament [discus intervertebralis] No differently than in the lumbar vertebrae, a path [canalis vertebralis] is provided in these ossicles for the dorsal medulla, and like the lumbar vertebrae they accommodate a way for three pairs of nerves 85 behind the back of their bodies (as we previously stated), and before their ascending // p. 105 // and descending processes. The lowest ossicle [vert. coccygea III] (6 in fig. 4), from which the dorsal medulla exits more or less unconnected and simple, ends randomly in cartilage like the ends of other bones in the non-caudate apes. But in dogs and caudate apes where these ossicles [vertebrae] are quite loose and mobile, a great many other ossicles are added to the lowest in a continuous series.

The sacrum and the coccyx are described in Galen as they are in the ape
These are not perforated for the dorsal medulla, but are long and solid; above and below, where they are interconnected like the vertebral bodies by cartilagimous ligament [discus intervertebralis], they are a little thicker; but in the middle they are thin. These, in a word, make up the tail. Since, therefore, in the ape and the dog a single bone [os sacrum] occurs immediately below the lumbar vertebrae combined from three bones (1-3 in fig. 4) as if from vertebrae in such a way that their connection differs from that of vertebrae chiefly because there is no cartilaginous ligament 86 as there is between the vertebral bodies (R, R in the fig. for ch. 14); and since this bone puts forth spines [crista sacralis mediana] that angle upward more than downward, and has foramina [ff. sacralia anteriora et posteriora] carved out before and behind for the second and third pairs of its own nerves [nervi sacrales I, II] (to grant Galen something here), 87 I judge the bone was described by him in place of the sacrum in his book On the Bones. Likewise, because in apes and dogs at least three bones (4-6 in fig. 4; cf. 1-3 in the same fig.) succeed after it, which also transmit the dorsal medulla and unlike the three bones of the sacrum in those animals have a cartilaginous ligament in their connection; and since even without long or extensive boiling or other great effort they can readily be torn apart no differently than lumbar vertebrae, and since these bones put forth nerves only from the back [facies dorsalis] of their bodies and not also toward the front, I am convinced that Galen had given them the name of the coccyx. I believe also that he had established special differences between his sacrum and the coccyx: in the connection between them, the emission of nerves, and the foramina. Indeed, because he attributed more cartilage to the bones of the coccyx than to the sacrum, I take it he meant that cartilage [discus intervertebralis] (R, R in the figure for ch. 14 and 3 of the figure inserted in ch. 40, bk. 2) which the ancients affirmed is the principal bond of the vertebral bodies, unlike Galen 88 — though I regularly call it cartilaginous ligament (as in fact it is). I do not at all agree with many self-described experts, corrupters of the works of Galen, who say that he was speaking here of the cartilage that attaches to the sides of the bones, since more of the cartilage, and indeed cartilaginous ligament, 89 exists in the depressions [pars lateralis, facies auricularis et tuberositas sacralis] (N, N, O, O, P Q in fig. 2) that receive the iliac bones, particularly in their posterior area, where the iliac bones separate a little from the sacrum, than in the bones which lie close beneath the connection of the iliac bones with the sacrum [art. sacro-iliaca], whether in ape (4-6 in fig. 4) or in man (D, E, F in fig. 1). Those corrupters, lest Galen seem to have passed over or ignored the six foramina [ff. sacralia anteriora] (the foramina of one side are marked 4, 5, 6 in fig. 1) add in his chapter on the coccyx that the nerves [n. coccygeus, plexus coccygeus] of that bone are also brought out anteriorly as well, 90 boldly arguing that this had been omitted by the copyists. This is more to be condemned because, as before in the connection and meeting of the bones, now in the course and exit of the nerves they set aside every difference by which Galen learnedly and in true anatomical fashion distinguished the bones of his coccyx from those of the sacrum in the structure of apes and dogs, to which Galen’s descriptions will not afterward be able to be reconciled. Moreover, I am unable to conjecture how descriptions so augmented, or rather distorted and corrupted, are applied to the ten bones [os sacrum et os coccygis] of man lying beneath the lumbar vertebrae. To make no mention of the mutual attachment of the first six bones which I shall describe in the section on the sacrum, as well as the structure in a single series from a more or less wide base [basis ossis sacri] to a point [apex ossis sacri], the equal distribution of nerves forward and backward, and the fact that the spines [crista sacralis mediana] do not incline upward, I do not know why Galen neglected the four bones [vertebrae coccygeae I-IV] (G-K in figs. 1, 3) about which I have written in the section on the coccyx and which provide no path for the dorsal medulla, when the upper two of these are so conspicuous and have a position in that // p. 106 // structure, and with the others perform such a useful function that they ought not be lightly passed over by anyone dissecting the human body. But the perverters of Galen’s books say that our coccyx was passed over purposefully by him because its bones are not unearthed from graves with the sacrum, or because Galen was unwilling to present them — like the hyoid bone, the bone of the heart, 91 and the sesamoid ossicles — to beginners in his book On the Bones; or because he considered all four bones equivalent to a single cartilage. Finally, they consider it of the greatest importance that Galen should not be inconsistent in his books On the Use of the Parts with his other writings; so that the three bones of his sacrum should be counted as three, and the three bones of his coccyx as only a single bone, and so that our coccyx should be the cartilage that the said in this work attaches to the extremity of the fourth bone of the sacrum. 92 When these things are recalled and I find them cited in opposition to my views, I seem to hear those who quite absurdly and with great pomposity try to show that Galen, Avicenna, and who knows what physicians and philosophers or conflicting works of the same author do not disagree with each other. They read things into the writings which their authors did not think even in a dream, and which are altogether foreign to their views. If Galen omitted our coccyx in the eleventh and twelfth chapter of his book On the Bones because its discussion was not relevant for those who were being introduced to the subject, he indubitably mentioned our coccyx at the end of his book On the Bones as he did the other ossicles which he described more fully elsewhere — though no mention of this coccyx of ours occurs in any book of Galen. 93 The fact that it occurs separated from the sacrum in graves and sepulchers, and its ossicles are seen scattered like vertebrae, is ground for argument that Galen adapted descriptions of the ancients for his apes, supposedly because as their ligaments shrivel the simian bones succeeding the sacrum separate from each other, unlike the three lower bones of our sacrum. It is necessary with these people to base discussion only on a human sacrum made from the bones of an elderly person. For when five or only four bones making up our sacrum are found in man, they can in no way whatever be reconciled with Galen’s six bones, since not even the number of bones providing a path for the dorsal medulla matches. If bones that have separated from each other in cemeteries must be taken into consideration, what account is to be made of vertebrae, ribs, bones of the hand, foot, chest, and of nearly every part, since these present themselves parted and separated unlike the bones of our sacrum? When they imagine that Galen justifiably considered our coccyx bone a cartilage because its bones appear soft and cartilaginous in children, and, as they say, seem to be only four cartilages, it is as if Galen had constructed an account about children rather than persons of middle age, or about animals. But they too casually consider that in the makeup of many bones, in the entire system of epiphyses — particularly in their number — in the cartilages of the ribs [cart. costalis], and nearly a hundred other ways, this account of Galen more exactly fits apes and dogs, which are quite dry and extremely bony animals, so to speak, than man, who is nearly the dampest of all animals, and soft. 94 So far as I can tell, it would be possible to invent anything from these people, and impose it on one’s hearers with an opinion of Galen that they have perverted, did I not for my part show the true structure of man to those who are eager to learn. I do not think it altogether incumbent on me to alter the books of Galen as if they were sacred, when in the great and infinite difference between man and the apes and other beasts upon which Galen especially worked, Galen’s account is more in conformity with them than with man — particularly whenever that difference, however manifest, does not appear to have been noticed by Galen or otherwise expressed. Indeed, he himself should be heeded in the beginning of the third book // p. 107 // of his Commentary on Hippocrates’ book On the Joints, when he says that he wrote his book On the Joints after carefully inspecting the peculiar character of each bone especially in the actual dried-up cadavers of humans, and if not these then certainly in apes. 95 In this way he clearly indicates at least that he has spared no effort to explain apes, and that they are extremely similar to man in the construction of their bones.

More than Galen’s other anatomical works, his work On the Bones should be attributed to him
For this reason, none of all Galen’s anatomical works seems more attributable to him than this one On the Bones. This is certainly the one which he so often recommends and seriously considers worthy of repeated reading and being committed to memory because it is so concise. Though it more exactly fits apes 96 than humans, it contains fewer false descriptions and errors than all the others, and I am accustomed in the schools to mention it openly, altogether dispassionately (may the gods prosper me) and with approval in the midst of demonstrations. But no matter what, I am unable to escape the calumnies and false detractions of certain vicious old men who are withering with envy because they themselves are ignorant of these things.



Book One -- The things that sustain and support the entire body, and what braces and attaches them all. [the bones and the ligaments that interconnect them]