. The anatomy of the human body. Human anatomy; Anatomy. ARTICULATIONS OF THE VERTEBRAL COLUMN. 117 59, 60, and 68) consists of a kind of disc, which fills up the lenticular space between the bodies of the vertebrae, and might, with propriety, be called intervertebral disc. Each disc has the form of a double convex lens, and is so closely united by its upper and under surfaces to the corresponding vertebrae, that it is easier to break the bones than to destroy this connexion. Its circumference adheres to the anterior and posterior com- mon ligaments, and contributes to form the intervertebral
. The anatomy of the human body. Human anatomy; Anatomy. ARTICULATIONS OF THE VERTEBRAL COLUMN. 117 59, 60, and 68) consists of a kind of disc, which fills up the lenticular space between the bodies of the vertebrae, and might, with propriety, be called intervertebral disc. Each disc has the form of a double convex lens, and is so closely united by its upper and under surfaces to the corresponding vertebrae, that it is easier to break the bones than to destroy this connexion. Its circumference adheres to the anterior and posterior com- mon ligaments, and contributes to form the intervertebral foramina. In the dorsal region it also forms part of the angular facette wliich articulates with the ribs. The thickness of the intervertebral substance is not the same in all the regions of the spinal column, be- ing greatest at the lower parts. The proportion between the thickness of the discs and the bodies of the vertebrae is exactly measured by that of the intervertebral space, and is not the same in all the regions. In the lumbar region the thickness of the disc is half that of the corresponding vertebrae ; in the dorsal region it is a third ; and in the cervi- cal region it is a little more than a half* The intervertebral substance is not equally thick throughout. From its lenticular form, it must be thicker at the -centre than at the circumference ; in the neck and in the loins it is thicker in front than behind ; in the back the opposite prevails, and by this inequality the discs concur in producing the alternate curves of the vertebral column. Abnormal curvatures are in a great measure caused by unequal thickness of these dies, and I have often had opportunities to convince myself that compression of this substance on the side towards which the inclination takes place is the most common origin of the deformity. The thickness of the discs varies in different circumstances. Thus, after prolonged standing in the erect posture, the height of the body becomes diminished fr
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