The importance of back and neck pain in our society is underscored by the following: (1) the cost of back pain in the United States exceeds $100 billion annually; approximately one-third of these costs are direct health care expenses, and two-thirds are indirect costs resulting from loss of wages and productivity; (2) back symptoms are the most common cause of disability in those <45 years; (3) low back pain is the second most common reason for visiting a physician in the United States; and (4) ~1% of the U.S. population is chronically disabled because of back pain.
The anterior portion of the spine consists of cylindrical vertebral bodies separated by intervertebral disks and held together by the anterior and posterior longitudinal ligaments. The intervertebral disks are composed of a central gelatinous nucleus pulposus surrounded by a tough cartilaginous ring, the annulus fibrosis. Disks are responsible for 25% of spinal column length and allow the bony vertebrae to move easily upon each other (Figs. 15-1 and 15-2). Desiccation of the nucleus pulposus and degeneration of the annulus fibrosus increase with age and results in loss of height. The disks are largest in the cervical and lumbar regions where movements of the spine are greatest. The functions of the anterior spine are to absorb the shock of body movements such as walking and running, and to protect the contents of the spinal canal.
Vertebral anatomy. (From A Gauthier Cornuelle, DH Gronefeld: Radiographic Anatomy Positioning. New York, McGraw-Hill, 1998; with permission.)
Spinal column. (From A Gauthier Cornuelle, DH Gronefeld: Radiographic Anatomy Positioning. New York, McGraw-Hill, 1998; with permission.)
The posterior portion of the spine consists of the vertebral arches and processes. Each arch consists of paired cylindrical pedicles anteriorly and paired laminae posteriorly. The vertebral arch also gives rise to two transverse processes laterally, one spinous process posteriorly, plus two superior and two inferior articular facets. The apposition of a superior and inferior facet constitutes a facet joint. The functions of the posterior spine are to protect the spinal cord and nerves within the spinal canal and to provide an anchor for the attachment of muscles and ligaments. The contraction of muscles attached to the spinous and transverse processes and laminae works like a system of pulleys and levers that results in flexion, extension, and lateral bending movements of the spine.
Nerve root injury (radiculopathy) is a common cause of neck, arm, low back, buttock, and leg pain (Figs. 23-2 and 23-3). The nerve roots exit at a level above their respective vertebral bodies in the cervical region (e.g., the C7 nerve root exits at the C6-C7 level) and below their respective vertebral bodies in the thoracic and lumbar regions (e.g., the T1 nerve root exits at the T1-T2 level). The cervical nerve roots follow a short ...