Human physiology / by William Furneaux.

  • William Samuel Furneaux
Date:
1909
Catalogue details

Licence: In copyright

Credit: Human physiology / by William Furneaux. Source: Wellcome Collection.

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    for the muscles by which we are enabled to bend the back and to move those bones that articulate with the vertebral column. Between the bodies of the vertebrae are pads of elastic cartilage or gristle called intervertebral cartilages. These unite the vertebrae, and form with them a flexible column. In old age the cartilages of the backbone become hard and less flexible, so that the back can no longer be bent, except to a very slight extent. The points in which these vertebrce differ from each other may receive a passing notice. The bodies of the vertebroe increase in size from the first cervical to the lowest lumbar, so as to be able to support the greater weight they have to bear. The bodies of the cervical vertebra: being small, we have seven joints in a short column of bones. This gives great freedom of motion to the head and neck. The first two cervical vertebrae will be specially described in our next lesson. The long spinous pro- cesses of the dorsal vertebrcE, which show so plainly in the backs of thin persons, and the large spinous and lateral processes of the lumbar vertebrae, serve for the attach- ment of the powerful muscles by which we are enabled to bend the body. The dorsal vertebrcz are also provided each with two facets, sometimes called the Fig. i4._First Dorsal Vertebra, with cesses, with which the heads of the the first pair of Kibs, and a portion of ribs form movable joints. the Sternum. It will now be seen that a number of these vertebrae, arranged in a column, will not only form a powerful and flexible support, but that the I, body of the vertebra; 2, spin.al cavity ; 3, spinous process ; 4, lateral processes ; 5, articular facet of lateral process ; 6, articular facet for the head of the rib. (These two facets form, with the rib, movable joints.) 7, ribs ; 8, cartilage or gristle connecting the ribs with the sternum ; 9, sternum, or breast-bone. vertebral arches will form a long bony tube. This tube is called the spinal canal, and contains the great nerve known as the spinal cord, to which the bones of the vertebral column serve as a strong protection. The ribs or costae, twenty-four in number, are curved bones, connected in pairs with the dorsal vertebrae behind, and, except the last two pairs, with the sternum (Gr. sternon, the breast) or breast-bone in front. Each pair of ribs thus forms a circular arch called a costal arch (fig. 14)- That portion of the rib which forms a movable joint with the articular process of the dorsal vertebrae is termed its head. The other end is in most cases attached by
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