Diagnosis and treatment of surgical diseases of the spinal cord and its membranes / by Charles A. Elsberg.

  • Elsberg, Charles A. (Charles Albert), 1871-1948.
Date:
1916
Catalogue details

Licence: Public Domain Mark

Credit: Diagnosis and treatment of surgical diseases of the spinal cord and its membranes / by Charles A. Elsberg. Source: Wellcome Collection.

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    termed a segment. The nerve roots are, therefore, the guides to the segments of the cord, the boundaries of each segment corresponding to a horizontal plane through the cord midway between two adjacent nerve roots. There are thirty-one pairs of spinal nerves—eight cervical, twelve dorsal or thoracic, five lumbar, five sacral, one coccygeal. The first pair of cervical nerves emerge from the vertebral canal between the occipital bone and the atlas; the first to eighth cervical roots are named after the lower of the two vertebre which form the intervertebral foramen of exit of the nerve. The eighth cervical nerve roots emerge from the Fic. 7.—The structure of posterior spinal roots in the cervical region. Note the separate root bundles which unite near the dural opening (diagrammatic). foramen between the seventh cervical and first thoracic vertebre. In the thoracic, lumbar and sacral areas the spinal nerves are named after the upper of the two vertebre which form the corresponding intervertebral foramen (Fig. 15). Each spinal nerve is formed by the coalescence of two roots which spring from the lateral aspects of the cord, the anterior or motor root which originates from the anterolateral groove and the posterior or sensory root from the posterolateral groove. The anterior and posterior roots perforate the dural sheath separately with a thin septum of dura mater between them. In the cervical region the nerve bundles remain