Peripheral Distribution of Myelinated Nerve Fibers Through Gray Communicating Rami in Dog.

Abstract

The cervical, lower lumbar (below L. II) and sacral spinal nerves are connected with the sympathetic trunk only through gray communicating rami which, according to the current teaching, comprise no spinal nerve components, but only fibers of sympathetic origin. Certain clinical and experimental data strongly suggest that the gray communicating rami joining the brachial and lumbosacral plexuses also comprise afferent fibers of spinal ganglion origin.To test this hypothesis, the following experiments were carried out. Two series of dogs were subjected to operation. In the first series both roots of the thoracic spinal nerves from the 1st to the 8th inclusive were cut unilaterally just distal to the spinal ganglion, leaving the communicating rami intact. In some of the animals in the 2nd series both roots of the lumbar nerves, usually from the 1st to the 6th inclusive, were cut unilaterally distal to the spinal ganglia, in the others the left lumbar sympathetic trunk was resected above the level of the commu...