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

vertebral artery The vertebral arteries are major arteries An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry o ...

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 r ...

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 supplies the grey and white posterior columns of the spinal cord.

Structure

It passes posteriorly to descend the medulla passing in front of the posterior roots 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 the ...

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

vertebral canal 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 through which the spinal cord passes. It is a process of the dorsal body ca ...

through the

intervertebral foramina The intervertebral foramen (also called neural foramen, and often abbreviated as IV foramen or IVF) is a :wikt:foramen, foramen between two spinal vertebrae. Cervical vertebrae, Cervical, thoracic vertebrae, thoracic, and lumbar vertebrae all ...

, forming a plexus called the vasocorona with the anterior vertebral arteries. Below the

medulla spinalis The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spin ...

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 enlargeme ...

. Branches from the posterior spinal arteries form a free

anastomosis An anastomosis (, plural 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, leaf veins, or streams. Such a connection m ...

around the

posterior roots of the spinal nerves 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 ...

, and communicate, by means of very tortuous transverse branches, with the vessels of the opposite side. 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 ve ...

. The posterior spinal artery can often originate from the posterior inferior cerebellar artery, rather than the vertebral.

Functions

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

gracile nucleus In neuroanatomy, the dorsal column nuclei are a pair of nuclei in the dorsal columns in the brainstem. The name refers collectively to the cuneate nucleus and gracile nucleus, which are present at the bottom of the medulla oblongata. Both nucl ...

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 In neuroanatomy, the dorsal column nuclei are a pair of nuclei in the dorsal columns in the brainstem. The name refers collectively to the cuneate nucleus and gracile nucleus, which are present at the bottom of the medulla oblongata. Both nu ...

. 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 In neuroanatomy, the sensory decussation or decussation of the lemnisci is a decussation (i.e. crossover) of axons from the gracile nucleus and cuneate nucleus, which are responsible for fine touch, vibration, proprioception and two-point discri ...

, it would affect the

proprioception Proprioception ( ), also referred to as kinaesthesia (or kinesthesia), is the sense of self-movement, force, and body position. It is sometimes described as the "sixth sense". Proprioception is mediated by proprioceptors, mechanosensory neurons ...

, 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 spinothalamic tract is a part of the anterolateral system or the ventrolateral system, a sensory pathway to the thalamus. From the ventral posterolateral nucleus in the thalamus, sensory information is relayed upward to the somatosensory cor ...

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

References

External links

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