A manual of human anatomy : descriptive, practical, and general / by Robert Knox.

  • Robert Knox
Date:
1853
Catalogue details

Licence: Public Domain Mark

Credit: A manual of human anatomy : descriptive, practical, and general / by Robert Knox. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    PECULIAR CERVICAL VERTEBRAE—THE ATLAS. Meckel compares the posterior root of the transverse process of the cervical vertebrae to the transverse processes of the dorsal verte- brae ; and the anterior root to the ribs, which in the cervical vertebrae are rudimentary. But though followed in this by many good ana- tomists,* I have demonstrated the opinion to be an erroneous one. The anterior root of the transverse processes of the cervical vertebrai is composed of two distinct osseous elements, of which the anterior one alone is the rudimentary rib. Peculiar Cervical Vertebra:.—Every vertebra differs in some respects from all the others; but descriptive anatomists think it suffi- cient to attend to a certain number only in each region. In the cervical region we find three which have been so described; namely, 1, the first, or atlas; 2, the second, or dentata; 3, the seventh, or pi'oeminens. Fig. 8.f Fig. 9 + The Atlas.—This bone is so called from its supporting the head. It cannot well be mistaken for any other vertebra. In form it re- sembles a some- what irregularly shaped ring, the narrower and smaller portion of the ring or circle being in front. A ligament run- ning transversely across from one side to the other, divides the ring into two unequal parts; the one in front of the ligament is intended for the reception of the processus dentatus of the axis or 2nd cervical vertebra; through the larger circle, behind the ligament, passes the medulla spinalis, its membranes and vessels, together with the spinal accessory nerves. When we examine the vertebra in detail and endeavour to recognise in it the structures it may have in common with the other vertebra, and the modifications these may have undergone to fit the bone for its place and functions, we find, 1st, that it has no body properly speak- ing, the processus dentatus occupying its place ; 2nd, on the posterior * Quain, 5th edition by Sharpey and Quain, p. 7. f Fig. 8.—Atlas; upper surface— h, anterior margin of the ring of the atlas; g, articular surface for the play of the odontoid process of the second vertebra or axis; d, superior articular process, right side ; /, transverse process, in its base maybe seen the foramen for the passage of the vertebral artery; c, points to the tubercles to which the transverse ligament is attached ; e, points to the groove connecting the notch and vertebral foramen ; b, the commencement of the posterior part of the ring of the atlas ; i is placed in the anterior part of the foramen for the spinal marrow, and a short way behind the situation of the ligament. (See the illustrations of the ligaments.) t Fig. 9.—Atlas viewed from below.—a, tubercle, representing the spinous process. The other letters indicate the corresponding or similar structures as in the preceding figure.
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