The posterior spinal artery (dorsal spinal arteries) arises from the

vertebral artery The vertebral arteries are major artery, arteries of the neck. Typically, the vertebral arteries originate from the subclavian arteries. Each vessel courses superiorly along each side of the neck, merging within the skull to form the single, m ...

in 25% of humans or the

posterior inferior cerebellar artery The posterior inferior cerebellar artery (PICA) is the largest branch of the vertebral artery. It is one of the three main arteries that supply blood to the cerebellum, a part of the brain. Blockage of the posterior inferior cerebellar artery can ...

in 75% of humans, adjacent to the

medulla oblongata The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. It is anterior and partially inferior to the cerebellum. It is a cone-shaped neuronal mass responsible for autonomic (involun ...

. It is usually double, and spans the length of the spinal cord. It supplies the grey and white posterior columns of the spinal cord.

Structure

The posterior spinal artery arises above the

foramen magnum The foramen magnum () is a large, oval-shaped opening in the occipital bone of the skull. It is one of the several oval or circular openings (foramina) in the base of the skull. The spinal cord, an extension of the medulla oblongata, passes thro ...

. It passes posteriorly to descend the medulla passing through and behind of the

posterior roots The dorsal root of spinal nerve (or posterior root of spinal nerve or sensory root) is one of two "roots" which emerge from the spinal cord. It emerges directly from the spinal cord, and travels to the dorsal root ganglion. Nerve fibres with the v ...

of the

spinal nerves A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column. These are grouped into ...

. Along its course it is reinforced by a succession of segmental or radiculopial branches, which enter the

vertebral canal In human anatomy, the spinal canal, vertebral canal or spinal cavity is an elongated body cavity enclosed within the dorsal bony arches of the vertebral column, which contains the spinal cord, spinal roots and dorsal root ganglia. It is a proc ...

through the

intervertebral foramina The intervertebral foramen (also neural foramen) (often abbreviated as IV foramen or IVF) is an opening between (the intervertebral notches of) two pedicles (one above and one below) of adjacent vertebra in the articulated spine. Each interve ...

, forming a plexus called the

vasocorona In human anatomy, the spinal canal, vertebral canal or spinal cavity is an elongated body cavity enclosed within the dorsal bony arches of the vertebral column, which contains the spinal cord, spinal roots and dorsal root ganglia. It is a proc ...

with the anterior vertebral arteries. Below the

medulla spinalis The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...

and upper cervical spine, the posterior spinal arteries are rather discontinuous; unlike the anterior spinal artery, which can be traced as a distinct channel throughout its course, the posterior spinal arteries are seen as somewhat larger longitudinal channels of an extensive pial arterial meshwork. At the level of the conus medullaris, the posterior spinals are more frequently seen as distinct arteries, communicating with the anterior spinal artery to form a characteristic "basket" which angiographically defines the caudal extent of the spinal cord and its transition to the

cauda equina The cauda equina () is a bundle of spinal nerves and spinal nerve rootlets, consisting of the second through fifth lumbar nerve pairs, the first through fifth sacral nerve pairs, and the coccygeal nerve, all of which arise from the lumbar enl ...

Branches

Close to its origin each posterior spinal artery gives off an ascending branch, which ends ipsilaterally near the

fourth ventricle The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. These cavities, known collectively as the ventricular system, consist of the left and right lateral ventricles, the third ventricle, and the fourth ...

Anastomoses

Branches from the posterior spinal arteries form a free

anastomosis An anastomosis (, : anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf veins, or streams. Such a connection may be normal (su ...

around the posterior roots of the spinal nerves, and communicate, by means of very tortuous transverse branches, with the vessels of the opposite side. There are few anastomoses with the anterior spinal artery except at the inferior extremity of the spinal cord.

Functions

Most cranially, the posterior spinal artery supplies the dorsal column of the closed medulla containing fasiculus gracilis,

gracile nucleus The dorsal column nuclei are a pair of nuclei in the dorsal columns of the dorsal column–medial lemniscus pathway (DCML) in the brainstem. The name refers collectively to the cuneate nucleus and gracile nucleus, which are situated at the lo ...

fasciculus cuneatus ''Fasciculus vesanus'' is an extinct species of stem-group ctenophores known from the Burgess Shale of British Columbia, Canada. It is dated to and belongs to middle Cambrian strata. The species is remarkable for its two sets of long and short ...

, and

cuneate nucleus The dorsal column nuclei are a pair of nuclei in the dorsal columns of the dorsal column–medial lemniscus pathway (DCML) in the brainstem. The name refers collectively to the cuneate nucleus and gracile nucleus, which are situated at the l ...

. At the spinal cord level, the posterior spinal artery supplies the dorsal and lateral column as well as the peripheral part of the anterior and central column.

Clinical significance

Disruption of blood supply to this particular artery in the medulla would result in a number of sensory deficits. If occlusion occurs above the level of

sensory decussation The sensory decussation or decussation of the lemnisci is a decussation (a crossing over) of axons from the gracile nucleus and cuneate nucleus, known together as the dorsal column nuclei. The dorsal column nuclei are responsible for fine touc ...

, it would affect the

proprioception Proprioception ( ) is the sense of self-movement, force, and body position. Proprioception is mediated by proprioceptors, a type of sensory receptor, located within muscles, tendons, and joints. Most animals possess multiple subtypes of propri ...

, vibration, and two-point discrimination of the contralateral side of the body. When occlusion occurs below the level of sensory decussation, however, it would cause the effect on the ipsilateral side instead. Particularly at the upper cervical spinal cord where the posterior spinal artery supplies some parts of the ventral column, lesion might extend to the

anterolateral system The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...

and triggers the loss of pain and temperature sensation on the contralateral side of the body.

References

External links

Diagram
at nih.gov * at anaesthesiauk.com {{Authority control Arteries of the head and neck