| Bones.The only subcutaneous parts of the vertebral column are the apices of the spinous processes. These are distinguishable at the bottom of a furrow which runs down the middle line of the back from the external occipital protuberance to the middle of the sacrum. In the cervical region the furrow is broad and ends below in a conspicuous projection caused by the spinous processes of the seventh cervical and first thoracic vertebræ. Above this, the spinous process of the sixth cervical vertebra sometimes forms a projection; the other cervical spinous processes are sunken, but that of the axis can be felt. In the thoracic region the furrow is shallow and during stooping disappears, and then the spinous processes become more or less visible; the markings produced by them are small and close together. In the lumbar region the furrow is deep and the situations of the spinous processes are frequently indicated by little pits or depressions, especially when the muscles in the loins are well-developed. In the sacral region the furrow is shallower, presenting a flattened area which ends below at the most prominent part of the dorsal surface of the sacrum, i. e., the spinous process of the third sacral vertebra. At the bottom of the sacral furrow the irregular dorsal surface of the bone may be felt, and below this, in the deep groove running to the anus, the coccyx. |
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