COMPARISON OF SCIATIC NERVE COURSE IN AMPHIBIANS, REPTILES AND MAMMALS

Abstract

The sciatic nerve is the longest single nerve in the body arising from the lower part of the sacral plexus; the sciatic nerve enters the gluteal region by the greater sciatic foramen of the hip bone. It continues down the posterior compartment of the thigh, until it separates into the tibial nerve and the common peroneal nerve. The location of this division varies between individuals. Various techniques were used for the study of the sciatic nerve anatomy that are able to depict the sciatic nerves division. The purpose of this study is to compare sciatic nerve anatomy, its branches to different muscles in amphibian (Frog), reptiles (Uromastix) and mammals (Rabbit) and how these morphometric characteristics vary in these animals. The dissection was done to identify the location and branches of sciatic nerve from both the right and left side taken from adult & both sexes of Frog, Uromastix and Rabbit and photographs had been taken to understand comparative anatomy of sciatic nerve in these animals. The sciatic nerve course observed after dissection was different among these animals with respect to its branching to different muscles and diameter. The location of formation and division of sciatic nerve vary from animal to animal. This variance is due to difference in number of spinal nerves. In frog, there are ten spinal nerves (nine in Rana tigrina); in Uromastix, sixteen spinal nerves; while in Rabbit thirty-seven spinal nerves have been observed. Sciatic nerve thickness also varied among these animals. There is a clear difference in the course of sciatic nerve among these three animals, it is definitely on the basis of their branches and difference in diameter innervating both slow and fast muscle fiber types indicate major differences in locomotory pattern.