Intramedullary course of the dorsal-root fibers of the first three cervical nerves

✍ Scribed by S. W. Ranson; Helen K. Davenport; E. A. Doles

• Publisher: John Wiley and Sons
• Year: 1932
• Tongue: English
• Weight: 548 KB
• Volume: 54
• Category: Article
• ISSN: 0021-9967
• DOI: 10.1002/cne.900540102

✦ Synopsis

The first three cervical dorsal roots and the corresponding segments of the spinal cord play an important r81e in the cervical tonic and righting reflexes (Magnus, '24). For this reason it seemed desirable to have more precise information about the intramedullary course and termination of these root fibers. METHOD I n four cats the first three cervical dorsal roots were sectioned bilaterally and the animals mere killed after fifteen to twenty-one days. The brain stem and cervical cord mere fixed in BIiiller's fluid and the material stained by the Marchi method. Nearly complete series of sections of the pons and mednlla oblongata were mounted, as well as selected sections from each of the cervical segments of the cord.

DISTRIBUTION I N T H E SPINAL CORD

The fibers from the first three cervical dorsal roots occupy the lateral part of the posterior funiculus in the corresponding segments of the cord (figs. and). Both the ascend- ing and descending branches of the root fibers are found in this area, and since the area increases in extent and density in these cervical segments from below upward, the bulk of the ascending fibers must be greater than that of the descending fibers. This must mean that the descending liranches are 1