Answer
The vertebral column is composed of 33 smaller bones called vertebrae (sing. vertebra). There are special vertebrae but the following are the features of the typical unspecialized vertebra. These features include body, vertebral foramen, vertebral arch, pedicle, lamina, spinous process, transverse process, articular facets, and intervertebral foramina.
The body is an anterior ovoid structure which consists of a thin shell of compact bone around a mass of cancellous bone and red bone marrow. The next notable feature is the vertebral foramen, a trianguloid space between the vertebral arch and the body . This foramen in each vertebra is part of the vertebral canal in which lies the spinal cord. Posterior to each body is a bony arch called the vertebral arch; it is formed by paired pillar-like pedicles a pair of bony plates or laminae.
Two other prominent features of the typical vertebra are the spinous and transverse processes. The spinous process extends from the apex of the arch and projects posteriorly and downward . The transverse process extends laterally from the juncture of pedicle and lamina. Both processes provide points of attachment for ligaments, ribs and muscles.
Work Step by Step
The articular surfaces are also important features of vertebrae. The superior articular processes of a vertebra project upward to meet a pair of inferior articular processes of the superior adjacent vertebra. These processes contact at a pair of flat articular surfaces facing each other. The meeting of these structures serves to stabilize the vertebral column and helps it to resist twisting which is potentially injurious to the spinal cord.
The intervertebral foramina are openings between neighboring vertebrae. Each foramen is formed by an inferior vertebral notch in the pedicle of the superior (above)vertebra and a superior vertebral notch in the pedicle of adjacent inferior (below) vertebra. These intervertebral foramina allow spinal nerves to enter the vertebral canal and make contact with the spinal cord.
Intervertebral discs
Closely related to vertebrae and the functions of the vertebral column are the intervertebral discs. These structures are cartilaginous pads/ bodies between most vertebrae. There are 23 intervertebral discs: the first is located between the second and third cervical vertebrae, and the last lies between the last lumbar vertebra and the sacrum. Each intervertebral disc consists of a nucleus pulposus -- an inner gelatinous center-- and an outer ring of cartilage called the annulus fibrosus, which encloses it. The intervertebral discs support the weight of the body, the act as shock absorbers and help to hold the vertebrae together.
