White ramus communicans

White ramus communicans
Scheme showing structure of a typical spinal nerve. 1. Somatic efferent. 2. Somatic afferent. 3, 4, 5. Sympathetic efferent. 6, 7. Sympathetic afferent.
Diagram of the course and branches of a typical intercostal nerve. (Rami communicantes labeled at center.)
Details
Identifiers
Latin	ramus communicans albus nervi spinalis
TA	A14.3.01.007
FMA	5875
*Anatomical terminology* [edit on Wikidata]

The white ramus communicans (plural: rami communicantes) from Latin ramus (branch) and communicans (communicating) is the preganglionic sympathetic outflow nerve tract from the spinal cord.

Each of the thoracic, and the first and second lumbar nerves contribute a white ramus communicans to the adjoining sympathetic ganglion, unlike the gray rami which are located at each spinal level.^[1] White rami communicantes contain both myelinated and unmyelinated preganglionic sympathetic fibers, (GVE and GVA). The white ramus appears white because they are more myelinated than unmyelinated fibers unlike the gray rami.

Structure

The white rami communicantes are the preganglionic sympathetic outflow from the spinal cord.

The cell bodies for the preganglionic sympathetic myelinated fibers in the white rami communicantes lie in the ipsilateral (same sided) intermediolateral cell column in the spinal cord which extends from T1-L2. These rami also contain general visceral afferent fibers (sensory from the organs) whose primary cell bodies reside dorsal root ganglia (which then synapse in the dorsal horn). The preganglionic sympathetic fibers will enter into the sympathetic trunk and either synapse at the ganglion on the same level, or travel up or down the sympathetic trunk to arrive at the correct spinal level for their action. Once they synapse in the sympathetic ganglion in the sympathetic trunk, they exit the trunk as gray rami to join the spinal nerve and innervate the appropriate structure. Even though the sympathetic trunk extends below L2, there are no more white rami communicantes below L2 because the intermediolateral cell column ends before this. The fibers of the sympathetic trunk above and below T1-L2 originate from white rami communicantes within T1-L2. Above and below T1-L2 there are only gray rami. Cell column are the important features of white rami communicates.

Additional Images

Deep and superficial dissection of the lumbar plexus.
Thoracic portion of the sympathetic trunk.

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

↑ "Dissector Answers - Kidney & Retroperitoneum". Retrieved 2007-11-13.

External links

Atlas image: n3a6p1 at the University of Michigan Health System - "Autonomic Connections of the Spinal Cord"
Overview and diagram

Anatomy of the autonomic nervous system

Head

Sympathetic	Ciliary ganglion: roots Sensory Sympathetic Short ciliary

Parasympathetic	Ciliary ganglion: roots Sensory Parasympathetic Short ciliary Pterygopalatine ganglion: deep petrosal nerve of pterygoid canal branches of distribution: greater palatine inferior posterior nasal branches lesser palatine nasopalatine medial superior posterior nasal branches pharyngeal Submandibular ganglion Otic ganglion

Neck

Sympathetic	paravertebral ganglia: Cervical ganglia Superior Middle Inferior Stellate ganglion prevertebral plexus: Cavernous plexus Internal carotid

Chest

Sympathetic	paravertebral ganglia: Thoracic ganglia prevertebral plexus: Cardiac plexus Esophageal plexus Pulmonary plexus Thoracic aortic plexus splanchnic nerves: cardiopulmonary thoracic cardiac nerves: Superior Middle Inferior

Abdomen

Sympathetic	paravertebral ganglia: Lumbar ganglia prevertebral ganglia: Celiac ganglia Aorticorenal Superior mesenteric ganglion Inferior mesenteric ganglion prevertebral plexus: Celiac plexus Hepatic Splenic Pancreatic aorticorenal Abdominal aortic plexus Renal/Suprarenal Superior mesenteric Gastric Inferior mesenteric Spermatic Ovarian Superior hypogastric hypogastric nerve Superior rectal Inferior hypogastric Vesical Prostatic / Cavernous nerves of penis Uterovaginal Middle rectal splanchnic nerves: Lumbar splanchnic nerves

Enteric	Submucous plexus Myenteric plexus

Pelvis

Sympathetic	paravertebral ganglia: Sacral ganglia Ganglion impar splanchnic nerves: Sacral splanchnic nerves

Parasympathetic	splanchnic nerves: Pelvic splanchnic nerves

Nervous tissue

CNS

Tissue Types

Cell Types

Neuronal

Glial

insulating:	Myelination: Oligodendrocyte

other	Astrocyte Radial glial cell Ependymal cells Tanycyte Microglia

PNS

General	Posterior Root Ganglion Ramus Anterior Root Ramus Ramus communicans Gray White Autonomic ganglion (Preganglionic nerve fibers Postganglionic nerve fibers)

Connective tissues	epineurium perineurium endoneurium nerve fascicle

Neuroglia	Myelination: Schwann cell Neurolemma Myelin incisure Node of Ranvier Internodal segment Satellite glial cell

Neurons/
nerve fibers

Parts

Soma	Axon hillock

Axon	Axon terminals Axoplasm Axolemma Neurofibril/neurofilament

Dendrite	Nissl body Dendritic spine Apical dendrite/Basal dendrite

Types

Afferent nerve fiber/
Sensory nerve

Efferent nerve fiber/
Motor neuron

Termination

Synapse	Electrical synapse/Gap junction Chemical synapse Synaptic vesicle Active zone Postsynaptic density Autapse Ribbon synapse Neuromuscular junction

Sensory receptors	Meissner's corpuscle Merkel nerve ending Pacinian corpuscle Ruffini ending Muscle spindle Free nerve ending Olfactory receptor neuron Photoreceptor cell Hair cell Taste bud

This article is issued from Wikipedia - version of the 11/12/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.

White ramus communicans

Structure

Additional Images

See also

References

External links