Distribution of afferent fibers via the sympathetic trunks and gray communicating rami to the brachial and lumbosacral plexuses
✍ Scribed by Albert Kuntz; D. Ivan Farnsworth
- Publisher
- John Wiley and Sons
- Year
- 1931
- Tongue
- English
- Weight
- 569 KB
- Volume
- 53
- Category
- Article
- ISSN
- 0021-9967
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✦ Synopsis
The sympathetic trunk is connected with the spinal nerves by means of white and gray communicating rami. The white communicating rami are composed mainly of visceral afferent and preganglionic visceral efferent fibers. The gray communicating rami are composed mainly of sympathetic fibers which take origin in the ganglia of the sympathetic trunk and join the spinal nerves for peripheral distribution. The majority of the visceral afferent and preganglionic visceral efferent fibers are myelinated, but they exhibit a relatively wide range of variation in caliber. The majority of the sympathetic fibers are unmyelinated and of relatively small caliber. The gray communicating rami, in general, join the spinal nerves proximal to the origin of the corresponding white rami. I n many instances, however, the white and gray communicating rami cannot be separated from each other and the sympathetic fibers intermingle with the preganglionic and visceral afferent fibers. Certain of the spinal nerves, however-viz., the cervical, lower lumbar, and upper sacral nerves --contain neither preganglionic nor visceral afferent fibers. Neither is the sympathetic trunk connected with any of the sacral nerves by means of a white communicating ramus. The sympathetic trunk, therefore, is connected with the 389