The spinal, or vertebral, column is one of the primary support structures for the human skeleton. Made up of separate, pseudoseparate, and fused |vertebrae|, the |spine| features a great deal of articulation, allowing support and movement of the |skull|, ~flexion~ of the neck and back, anchor sites for the |ribs| (which enclose the abdominal cavity), and support and protection for the |spinal cord|. The |spine| is composed of seven |cervical vertebrae|, forming the neck, twelve |thoracic vertebrae|, which form the upper back, and five |lumbar vertebrae|, which form the lower back. Also part of the spinal column is the |sacrum|, a bone made of five fused |vertebrae| which anchors the |spine| to the pelvic girdle, and the |coccyx|, or tailbone, a semi-flexible series of four or less |vertebrae| which help to protect the lower alimentary tract. Between each vertebra is an intervertebral disk made of ~cartilage~, which acts as a |shock| absorber, to cushion the |vertebral column| from trauma. The |spine| is held together by a series of ~ligaments~, including the intertransverse ligaments which run the length of the |spine|, attached to the |transverse processes| of each vertebra. The |spinal cord|, which serves as the primary ~nerve~ pathway to and from the |brain|, proceeds down a canal in the center of the spinal column.
