white rami communicantes

white ra·mi com·mu·ni·can·tes

[TA]
short nerves arising from the initial portion of the anterior primary rami of the thoracic and upper lumbar spinal nerves through which all presynaptic sympathetic nerve fibers must pass to reach the sympathetic trunks; also conveyed by the white rami communicantes are visceral afferent (sensory) fibers that were conveyed to the sympathetic trunks in splanchnic nerves. Most fibers conveyed by the white rami communicantes are myelinated.
References in periodicals archive ?
There, it synapses with second order neurons whose pre-ganglionic cell bodies give rise to axons, which exit the white rami communicantes of the spinal cord via the anterior horn and enter the sympathetic chain in the neck, synapsing in the superior cervical ganglion.