In human anatomy, the spinal canal, vertebral canal or spinal cavity is an elongated body cavity enclosed within the neural arch of the vertebral column, which contains the spinal cord, and dorsal root ganglia. It is a process of the dorsal body cavity formed by alignment of the vertebral foramina. Under the vertebral arches, the spinal canal is also covered anteriorly by the posterior longitudinal ligament and posteriorly by the ligamentum flavum. The potential space between these ligaments and the dura mater covering the spinal cord is known as the epidural space. exit the spinal canal via the intervertebral foramina under the corresponding vertebral pedicles.
In humans, the spinal cord gets outgrown by the vertebral column during development into adulthood, and the lower section of the spinal canal is occupied by the filum terminale and a bundle of spinal nerves known as the cauda equina instead of the actual spinal cord, which finishes at the lumbar spine level.
Structure
The vertebral canal is enclosed anteriorly by the vertebral bodies, intervertebral discs, and the posterior longitudinal ligament; it is enclosed posteriorly by the vertebral laminae and the
ligamenta flava; laterally, it is incompletely enclosed by the pedicles with the interval between two adjacent pedicles on either side creating an intervertebral foramen (allowing the passage of the
Spinal nerve and radicular blood vessels).
The vertebral canal progressively narrows inferiorly.
Contents
The outermost layer of the
meninges, the
dura mater, is closely associated with the
arachnoid mater which in turn is loosely connected to the innermost layer, the
pia mater. The meninges divide the spinal canal into the
epidural space and the subarachnoid space. The
pia mater is closely attached to the
spinal cord. A
subdural space is generally only present due to trauma and/or pathological situations. The subarachnoid space is filled with cerebrospinal fluid and contains the vessels that supply the
spinal cord, namely the anterior spinal artery and the paired posterior spinal arteries, accompanied by corresponding
spinal veins. The anterior and posterior spinal arteries form
anastomoses known as the
vasocorona of the spinal cord and these supply nutrients to the canal. The
epidural space contains loose fatty tissue, and a network of large, thin-walled blood vessels called the internal vertebral venous plexuses.
Clinical significance
Spinal stenosis is a narrowing of the canal which can occur in any region of the spine and can be caused by a number of factors. It may result in
Myelopathy if the narrowed canal impinges on the spinal cord itself.
Spinal canal endoscopy can be used to investigate the epidural space, and is an important spinal Medical test.
History
The spinal canal was first described by
Jean Fernel.
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