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. Visceral 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
TA98	A14.3.01.007
TA2	6150
FMA	5875
Anatomical terminology [edit on Wikidata]

The white ramus communicans (pl.: 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 there are more myelinated than unmyelinated fibers unlike the gray rami.