The spinal canal (or vertebral canal or spinal cavity) is the canal that contains the spinal cord within the vertebral column. The spinal canal is formed by the

vertebrae The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic i ...

through which the spinal cord passes. It is a process of the dorsal body cavity. This canal is enclosed within the

foramen In anatomy and osteology, a foramen (;Entry "foramen"
in

of the vertebrae. In the intervertebral spaces, the canal is protected by the ligamentum flavum posteriorly and the

posterior longitudinal ligament The posterior longitudinal ligament is a ligament connecting the posterior surfaces of the vertebral bodies of all of the vertebrae. It weakly prevents hyperflexion of the vertebral column. It also prevents posterior spinal disc herniation, alth ...

anteriorly.

Structure

The outermost layer of the

meninges In anatomy, the meninges (, ''singular:'' meninx ( or ), ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in ...

, the dura mater, is closely associated with the

arachnoid mater The arachnoid mater (or simply arachnoid) is one of the three meninges, the protective membranes that cover the brain and spinal cord. It is so named because of its resemblance to a spider web. The arachnoid mater is a derivative of the neural ...

which in turn is loosely connected to the innermost layer, the

pia mater Pia mater ( or ),Entry "pia mater"
in
epidural space In anatomy, the epidural space is the potential space between the dura mater and vertebrae ( spine). The anatomy term "epidural space" has its origin in the Ancient Greek language; , "on, upon" + dura mater also known as "epidural cavity", "ext ...

and the

subarachnoid space In anatomy, the meninges (, ''singular:'' meninx ( or ), ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in ...

. The

pia mater Pia mater ( or ),Entry "pia mater"
in
spinal cord. A

subdural space The subdural space (or subdural cavity) is a potential space that can be opened by the separation of the arachnoid mater from the dura mater as the result of trauma, pathologic process, or the absence of cerebrospinal fluid as seen in a cadaver ...

is generally only present due to trauma and/or pathological situations. The

is filled with

cerebrospinal fluid Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates. CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the b ...

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 In anatomy, the epidural space is the potential space between the dura mater and vertebrae ( spine). The anatomy term "epidural space" has its origin in the Ancient Greek language; , "on, upon" + dura mater also known as "epidural cavity", "ext ...

contains loose fatty tissue, and a network of large, thin-walled blood vessels called the

internal vertebral venous plexuses The internal vertebral venous plexuses (intraspinal veins) lie within the vertebral canal in the epidural space, and receive tributaries from the bones and from the spinal cord. They form a closer network than the external plexuses, and, running ...

. The spinal canal is wider in the cervical spine region to provide space for the cervical enlargement of the spinal cord.

Clinical significance

Spinal stenosis Spinal stenosis is an abnormal narrowing of the spinal canal or neural foramen that results in pressure on the spinal cord or nerve roots. Symptoms may include pain, numbness, or weakness in the arms or legs. Symptoms are typically gradual in ...

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 be caused by

cervical myelopathy Myelopathy describes any neurologic deficit related to the spinal cord. The most common form of myelopathy in humans, '' cervical spondylotic myelopathy (CSM)'', also called ''degenerative cervical myelopathy'', results from narrowing of the spina ...

. Spinal canal

endoscopy An endoscopy is a procedure used in medicine to look inside the body. The endoscopy procedure uses an endoscope to examine the interior of a hollow organ or cavity of the body. Unlike many other medical imaging techniques, endoscopes are insert ...

can be used to investigate the epidural space, and is an important spinal diagnostic technique.

History

The spinal canal was first described by

Jean Fernel Jean François Fernel ( Latinized as Ioannes Fernelius; 1497 – 26 April 1558) was a French physician who introduced the term "physiology" to describe the study of the body's function. He was the first person to describe the spinal canal. The l ...

References

External links

Diagram at wisc.edu
{{Authority control Bones of the thorax Bones of the vertebral column