Spine Vertebral Column

About the Spine Vertebral Column

The vertebral column has 33 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral fused, and 4 coccygeal fused. It provides structural support, protects the spinal cord, and allows flexibility. Four curvatures are present in adults: the thoracic and sacral kyphoses are primary curves present before birth, while the cervical and lumbar lordoses are secondary curves that develop in infancy as the child begins to hold up the head and stand. Abnormal curvatures include scoliosis lateral, kyphosis excessive thoracic curve, and lordosis excessive lumbar curve. Each typical vertebra has a body, vertebral arch pedicles and laminae, vertebral foramen, transverse processes, spinous process, and articular processes facet joints. Intervertebral discs between vertebral bodies consist of annulus fibrosus tough outer ring and nucleus pulposus gelatinous core, acting as shock absorbers. Disc herniation occurs when the nucleus pulposus protrudes through the annulus, compressing nerve roots. The spinal cord runs from foramen magnum to L1-L2, giving rise to 31 pairs of spinal nerves 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal. Below L2, the cauda equina horse tail of nerve roots fills the spinal canal. Because the cord ends at about L1-L2, lumbar puncture to sample CSF is typically performed at the L3-L4 or L4-L5 level.