RESUMO
PURPOSE: In the hand surgery literature, more and more studies seem to indicate that the number of sympathetic fibers in the median and the ulnar nerves varies. However, there are no studies that confirm this suspicion. METHOD AND MATERIAL: Six hours post mortem samples were taken from the median and ulnar nerves, the superficial branch of the radial nerve, and from all digital nerves (each five females and males, average age 78 years). 13 samples were taken from one hand. To make sympathetic fibers visible, the immunohistochemical staining technique with tyrosinhydroxylase (TH) antibodies was used. Quantitative assessment of the sympathetic axons was made in whole cross-sections of the nerve. Statistical evaluation was performed with Wilcoxon rank-sum tests. RESULTS: The TH-positive axons are arranged in groups and are located in the endoneurium. No isolated sympathetic fibers were found in the peri- and epineurium. TH-positive axons were present on the arterial walls including the smallest arterioles. Proximal to the wrist, the median nerve has more sympathetic fibers than the ulnar nerve. The number, however, of the fibers was the same in each fascicle. A comparison of the digital nerves shows significant differences only between the radial nerve of the thumb and the ulnar nerve of the ring finger and between the radial nerve of the index finger and the ulnar nerve of the little finger. CONCLUSION: Although the median nerve proximal to the wrist has on average 20 fascicles and the ulnar nerve only 14, the number of fibres in each fascicle is the same. Therefore, based on the present study we conclude that there is no significant difference in the sympathetic fiber distribution of the two nerves.
