The anatomy of the human skeleton / by J. Ernest Frazer.

  • John Ernest Sullivan Frazer
Date:
1920
Catalogue details

Licence: In copyright

Credit: The anatomy of the human skeleton / by J. Ernest Frazer. Source: Wellcome Collection.

    23/396 page 9
    Chapter II VERTEBRAL COLUMN The human spinal column is made up of some thirty-three-segments or vertebra : the length of the column of bones is much increased by intervertebral discs of fibro- cartilage placed between the segments. The column has two main functions—(a) support of the trunk, etc., and trans¬ mission of its weight to the pelvis and lower extremities ; (b) protection of the spinal cord and its membranes. The structure of the whole column accords with the necessi¬ ties of these functions, and thus the vertebrae of which it is composed show their indi- Fig. 5.—A “typical” vertebra (mid-dorsal). From above and from the side. B. body; N.A. neural arch; S.F. spinal foramen; Sp. spinous process; T.P. transverse process; L. lamina ; P. pedicle ; Art. articular process. A rib is also indicated in position on one side. E. is the “ epiphysial plate ” or ring on the body. vidual agreement with the general arrangement of the whole : they are modified in details according to their position, but they are all built on the same general principle. This principle may be followed on a vertebra taken from the centre of the column and used as an illustration of the positions of the chief parts of a “ typical ” vertebra. Typical Vertebra (Fig. 5).—In front a strong body carries and transmits weight, while the neural arch behind this covers in the spinal cord : in conformity with this we find the strong pads of the intervertebral discs placed between the bodies of con¬ tiguous vertebrae, whereas the arches are connected by ligaments and tend to overlap one another. In the articulated column the successive arches and ligaments, with the backs of the bodies, enclose a neural or spinal canal for the cord and membranes, and the portion of the canal that is enclosed in the neural arch of each separate bone constitutes the spinal foramen of that vertebra. The neural arch has spinous and transverse processes projecting from its back and sides respectively, for the attachment of muscles and ligaments : the transverse processes also help to support ribs in their attachment to the column. Each half of the neural arch is divided by the position of the transverse process into a posterior
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