The intervertebral foramen, also known as the intervertebral neural foramen or intervertebral spinal foramen, is a small opening located between two adjacent vertebrae in the spine. It serves as a passageway for the spinal nerves and vessels to exit the spinal column and innervate the body.
Structure
The intervertebral foramen is formed by the superior and inferior articular processes of the adjacent vertebrae. The superior articular process is a bony protuberance that extends superiorly from the vertebral body, and the inferior articular process extends inferiorly from the vertebral body. The articular processes are connected by a joint called the zygapophyseal joint, which allows for slight movement between the vertebrae.
The intervertebral foramen is surrounded by the intervertebral disc, a fibrocartilaginous structure that acts as a shock absorber and allows for flexibility of the spine. The intervertebral disc is composed of the annulus fibrosus, a outer ring of fibrous tissue, and the nucleus pulposus, a gel-like substance located in the center of the disc.
Location
The intervertebral foramen is located between the adjacent vertebrae of the spine. The spine is divided into four regions: cervical, thoracic, lumbar, and sacral. The cervical spine consists of the first seven vertebrae and is located in the neck region. The thoracic spine consists of the next 12 vertebrae and is located in the upper back. The lumbar spine consists of the next five vertebrae and is located in the lower back. The sacral spine consists of the last five vertebrae and is located in the pelvis.
Function
The primary function of the intervertebral foramen is to allow the spinal nerves and vessels to exit the spinal column and innervate the body. The spinal nerves are responsible for transmitting sensory information from the body to the brain and motor information from the brain to the body. The spinal vessels, including the vertebral arteries and veins, provide blood supply to the spinal cord and surrounding structures.
The intervertebral foramen also plays a role in the movement and stability of the spine. The zygapophyseal joint, which surrounds the foramen, allows for slight movement between the vertebrae, allowing for flexibility of the spine. The intervertebral disc acts as a shock absorber, helping to distribute the weight of the body and protect the spine from impact.
Anatomical Variations
It is important to note that there can be variations in the size and shape of the intervertebral foramen among individuals. The size of the foramen is generally larger in the lower spine, particularly in the lumbar and sacral regions, due to the larger size of the spinal nerves in these regions.
In addition, there may be variations in the shape of the foramen due to individual differences in the shape of the vertebrae and the surrounding structures. For example, the intervertebral foramen may be more oval-shaped in some individuals, while in others it may be more circular.
Development
During fetal development, the intervertebral foramen is formed as the vertebrae begin to differentiate and grow. The articular processes and intervertebral discs begin to form, and the foramen is gradually established as a passageway for the spinal nerves and vessels.
Radiological Anatomy
Radiological imaging, such as CT scans and MRI, can be used to visualize the intervertebral foramen and surrounding structures. These imaging techniques can help to diagnose disorders of the foramen and guide treatment.
