An Inaugural Dissertation, Containing Some Observations on the Pelvis of the Mammalia, Which, Under the Presidency of Autenreith, Professor of Anatomy ... A Candidate for the Degree of Doctor of

Excerpt from An Inaugural Dissertation, Containing Some Observations on the Pelvis of the Mammalia, Which, Under the Presidency of Autenreith, Professor of Anatomy and Surgery, Was Offered for Public Examination by John Fischer: A Candidate for the Degree of Doctor of Medicine Tubingen, September, 1798

This is the reason chiefly why the larger os ilium of the mammalia is so much narrower than the same bone in man, and its crest especially narrow. Hence the greatest distinction arises in the ratio of the muscles of the pelvis and trunk; for instance, the dorsal muscles are very large in the rabbit, and the quadratus lumborum and psoas muscles of that animal which lie anteriorly on the longest transverse processes. These muscles, on both sides, completely hide the anterior aspect of the bodies of the lumbar vertebrae. There is no iliacus muscle, as there is evidently no room for it; but the quadratus lumborum being left on the lateral and superior margin of the pelvis, it ascends above that, resting almost on the anterior and lateral margin of the sacrum; posteriorly it appears to be joined in a manner to the pyriformus muscle of the true pelvis. The abdominal muscles are inserted into the anterior elongated margin of the ilium, Pouparts' ligaments being placed more at the side than in man, on account of the very broad symphysis of the bones of the pubes and thigh bones coming out from the sides of the pelvis, and placed chiefly in an oblique position.

On account of the narrowness of the ilium, these ligaments almost touched the inferior insertion of the quadratus lumborum, unless the psoas muscle came between them. All the crest of the ilium rises backwards above the os sacrum in the rabbits, and gives insertion to the dorsal muscles; hence the false pelvis is evidently wanting in that animal, and only the true pelvis is present. In other mammalia, as in the moles, not even by its margin does the os ilium look towards the cavity of the abdomen, the whole bone being retracted towards the back superiorly; other quadrupeds, as the horse, &c., at least possess some abdominal portion of the ilium; others truly, as the elephant, possess a very large portion, and which on this account resemble man; but I shall treat of these afterwards.

This absence of the false pelvis in most of the smaller animals, and the very narrow os ilium, render the extremity of the body posteriorly so narrow when compared to man, and by denying a broader place of insertion for the gluteal muscles, render the haunches of mammalia very slender. The first cause, in connection with the horizontal position of the trunk, easily explains why herniæ, which are of very frequent occurrence in man, are very rare among quadruped mammals; why no congenital hernia can occur in the rabbit, although the processes of peritonœum, which lead the testicle into the scrotum, remain open even in the adult animal, so that the testicles can very easily pass and re-pass from the cavity of the abdomen: why, moreover, hernias are of more frequent occurrence among those animals which have a certain kind of false pelvis, (as the horse,) which therefore have Pouparts' ligaments and the abdominal rings more transverse, and less situated at the side. It happens, indeed, that the thighs are bent towards the abdomen in almost all mammals, and the bony symphysis of the pubes is broader than in man; therefore, the lowest part of the abdomen is better protected, while the abdominal rings are at a greater distance from each other.

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