Posterior ramus of spinal nerve

Posterior ramus of spinal nerve
Nerve: Dorsal ramus of spinal nerve
Diagram of the course and branches of a typical intercostal nerve. (Posterior division labeled at upper right.)
Areas of distribution of the cutaneous branches of the posterior divisions of the spinal nerves. The areas of the medial branches are in black, those of the lateral in red.
Latin ramus posterior nervi spinalis
Gray's subject #209 921

The posterior (or dorsal) branches (or divisions) of the spinal nerves are as a rule smaller than the anterior divisions. They are also referred to as the dorsal rami.

They are directed backward, and, with the exceptions of those of the first cervical, the fourth and fifth sacral, and the coccygeal, divide into medial and lateral branches for the supply of the muscles and skin of the posterior part of the trunk.

Shortly after a spinal nerve exits the intervertebral foramen, it branches into the dorsal ramus, ventral ramus, and rami communicantes. Each of these latter three structures carries both sensory and motor information. Because each spinal nerve carries both sensory and motor information, spinal nerves are referred to as “mixed nerves.” Dorsal rami carry visceral motor, somatic motor, and sensory information to and from the skin and deep muscles of the back.

Dorsal rami remain distinct from each other, and each innervates a narrow strip of skin and muscle along the back, more or less at the level from which the ramus leaves the spinal nerve.

The smaller, posteriorly-directed major terminal branch (with the ventral primary ramus) of all 31 pairs of mixed spinal nerves, formed at the intervertebral foramen and turning abruptly posteriorly to divide into lateral and medial branches, both of which will supply the deep (true) muscles of the back. The medial branch (rami medialis ) of the dorsal primary ramus also supplies articular branches to the zygopophyseal joints and the periosteum of the vertebral arch. In the neck and upper back, the medial branch continues through the deep and superficial back muscles to supply overlying skin; in the lower back, the lateral branch does this. Nomina Anatomica lists dorsal primary rami as "rami dorsales" for each group of spinal nerves: 1) cervical (nervorum cervicalium ), 2) thoracic (nervorum thoracicorum ), 3) lumbar (nervorum lumbalium ), 4) sacral (nervorum sacralium ), and 5) coccygeal (nervi coccygei ).[1]

Synonyms: ramus dorsalis nervorum spinalium, ramus dorsalis, rami posteriores nervorum spinalium, dorsal branch, posterior primary division.

Contents

References

See also

Additional images

External links



Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Posterior root of spinal nerve — The formation of the spinal nerve from the dorsal and ventral roots Latin radix posterior Gray s …   Wikipedia

  • Ventral ramus of spinal nerve — Infobox Nerve Name = Ventral ramus Latin = ramus anterior nervi spinalis GraySubject = 210 GrayPage = 925 Caption = The formation of the spinal nerve from the dorsal and ventral roots. (Ventral ramus labeled at lower left.) Caption2 = Innervates …   Wikipedia

  • Dorsal ramus of spinal nerve — Infobox Nerve Name = PAGENAME Latin = ramus posterior nervi spinalis GraySubject = 209 GrayPage = 921 Caption = Diagram of the course and branches of a typical intercostal nerve. (Posterior division labeled at upper right.) Caption2 = Areas of… …   Wikipedia

  • Spinal nerve — Nerve: Spinal nerve The formation of the spinal nerve from the dorsal and ventral roots Scheme showin …   Wikipedia

  • Meningeal branches of spinal nerve — Nerve: Meningeal branches of spinal nerves Innervates intraspinal ligaments, vertebral periosteum, annulus fibrosus, zygapophysial joint capsules From Spinal nerve The meningeal branches of the spinal nerves (also known as recurrent meningeal… …   Wikipedia

  • Posterior branch of coccygeal nerve — Infobox Nerve Name = PAGENAME Latin = ramus posterior nervi coccygei GraySubject = 209 GrayPage = 925 Caption = Areas of distribution of the cutaneous branches of the posterior divisions of the spinal nerves. The areas of the medial branches are… …   Wikipedia

  • Posterior Rami Syndrome — Posterior Ramus Syndrome, also referred to as Thoracolumbar Junction Syndrome, Maigne Syndrome and Dorsal Ramus Syndrome is caused by the unexplained activation of the primary division of a posterior ramus of a spinal nerve (Dorsal ramus of… …   Wikipedia

  • Ramus — In anatomy, a branch, such as a branch of a blood vessel or nerve. For example, the ramus acetabularis arteriae circumflexae femoris medialis is the branch of an artery that goes to the socket of the hip joint. The plural of ramus is rami. * * *… …   Medical dictionary

  • ramus posterior nervi spinalis — [TA] posterior branch of spinal nerve: the posterior and usually smaller of the two branches into which each spinal nerve divides almost as soon as it emerges from the intervertebral foramen; the posterior branches supply the skin, muscles,… …   Medical dictionary

  • Nerve plexus — Spinal nerve Cervical plexus …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”