11.9: General Structure of a Vertebra
A typical vertebra, with the exception of the sacrum and coccyx, consists of a body, a vertebral arch, and seven different projections termed processes. The anterior portion of the vertebrae, the body, supports about half the body’s weight. The vertebral bodies progressively increase in size and thickness from the cervical region to the lumbar region of the vertebral column. The intervertebral discs present between the bodies of adjacent vertebrae firmly unites them, forming a continuous column.
The vertebral arch anchored to the vertebral body forms the posterior portion of each vertebra. It consists of four parts: the right and left pedicles, and the right and left laminae. Each pedicle forms the lateral sides of the vertebral arch. The large opening between the vertebral arch and body is the vertebral foramen. The vertebral foramina of all vertebrae align to form the vertebral canal, which serves as the bony protection and passageway for the spinal cord. When the vertebrae are aligned in the vertebral column, the concave notches in the margins of the pedicles of adjacent vertebrae align to form an intervertebral foramen, the opening through which a spinal nerve exits from the vertebral column.
Seven processes arise from the vertebral arch. Each pair of transverse processes projects laterally, arising from the junction point between the pedicle and lamina. The single spinous process projects posteriorly at the midline of the back. The vertebral spines can easily be felt as a series of bumps just under the skin down the midline of the back. The transverse and spinous processes serve as important muscle attachment sites. A superior articular process extends or faces upward, and an inferior articular process faces or projects downward on each side of a vertebrae. The paired superior articular processes of one vertebra join with the corresponding paired inferior articular processes from the adjacent superior vertebra.These junctions form slightly moveable joints, called facet joints, between the adjacent vertebrae. The shape and orientation of the articular processes vary in different regions of the vertebral column and play a significant role in determining the type and range of motion possible in each region.
This text is adapted from Openstax, Anatomy and Physiology 2e, Section 7.3: The vertebral column
