Manual of human osteology / by A. Francis Dixon.

Date:
1912
Catalogue details

Licence: In copyright

Credit: Manual of human osteology / by A. Francis Dixon. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    one fourth, of-thu entire length of the columna vertebralis in the living subject. The superimposed bodies of the verte- brae and the intervening intervertebral discs form the weight- carrying part of the vertebral column. The arcus vertebrae springs by two pillar-like portions, the pedicles or radices arcus vertebrae, from the posterior aspect of the body, and is completed posteriorly, behind the foramen vertebrale, by the union of two bony plates called lamuiae. These latter plates are connected along their upper and lower edges by elastic ligaments with the laminae of the vertebrae above and below. In this way the canalis vertebralis, which surrounds the spinal cord, is closed in posteriorly by the vertebral laminae and their connecting ligaments. The anterior wall of the canal is formed by the bodies of the vertebrae and the intervertebral discs. Attached to the arch of each vertebra are a number of projecting pieces of bone, or processes. One of these, the processus spinosus, is median in position, and springs from the junction of the laminae posteriorly. The others are attached in the region where the pedicle joins the lamina, and are three in number on each side. These paired pro- cesses are named as follows :— processus transversus—attached laterally at the junc- tion of the pedicle and lamina, and directed outwards ; processus articularis superior—attached to the upper aspect of the arch immediately behind the pedicle, and directed upwards ; processus articularis inferior—attached to the lower aspect of the arch just behind the pedicle. The articular processes are so called because they carry articular facets by means of which the arch of the vertebra articulates with the arches of the vertebrae above and below. These facets have a characteristically smooth appearance, and during life they are covered by a thin layer of articular carti- lage, which enables the facets of one vertebra to glide evenly on those of the vertebrae with which it is connected. If we examine a vertebra from its lateral aspect, we recognize that there is a notch, or hollow, between the inferior articular facet and the posterior aspect of the lower part of the body, and a similar shallower depression between the superior articular facet and the upper part, of the body. These notches, spoken of as the superior and inferior vertebral notches, incisura vertebralis superior and inferior, are separated from one another by the vertical thickness of the pedicle. When the