The vertebral foramen is a naturally occurring opening or passage through the spine, or the backbone. The term "vertebral" refers to the vertebral column, which is the clinical term for the spine. It gets its name from the segments of bone that it consists of, which are called vertebrae. The term "foramen," or foramina in plural form, indicates the opening itself. An alternate term for the vertebral foramen is the vertebral opening.
The purpose of the foramina is to permit connectivity between parts of the body. This can include arteries, muscles, veins and nerves. An example is the apical foramen, which connects the pulp of the tooth with its tissue support, called the periodontium, via a collection of blood vessels and nerves. The skull in particular has almost two dozen types of foramina that connect its various regions with its rich network of arteries, nerves and veins.
The vertebral foramen in particular forms a tunnel through which the spinal cord, or medulla spinalis, passes. This is a lengthy, slender, rope-like structure that stretches from the lower half of the brain stem, called the medulla oblongata. With the brain, the spinal cord is a major component of the body's central nervous system, transporting signals necessary for functions such as movement and sensory capabilities from the brain to the rest of the body. The vertebral foramen, as part of the spine, acts as a container and protective shield of the spinal cord. In addition, the long bundle of tissue is covered by a layer of membranes called meninges, which are also protective agents of the central nervous system.
The vertebral opening virtually lies in the middle of the spinal column. At one end is the body of the spine, a clam shell-shaped structure lined by the rib-joining site called the costal fovea. At the other end is a spaced-out tripod-shaped structure that contains features such as the laminae and the articular processes. This part consists of the vertebral arch, lending the column its stability.
Besides the spinal cord, the vertebral foramen is responsible for being a canal to other features of the central nervous system. For example, it carries the veins that connect the internal and external plexuses for communication between a variance of arteries. The dorsal root ganglia, which line the back of the spinal cord, is an assistant in connecting the central nervous system to the body's limbs and organs.