Origin and distribution of the ischiatic nerve in mixed-breed sheep

Abstract

Current research studied, by dissection, the origin and distribution of the ischiatic nerve in 30 fetuses of mixed-breed male or female sheep (Ovis aries), obtained from abortions, stillborns and natural deaths of pregnant females on farms in the Triângulo Mineiro region, state of Minas Gerais, Brazil. Formaldehyde 10% was injected through the cannulation of descending thoracic aorta and the material was kept immersed in the solution for at least 48 hours before dissection. The ischiatic nerve originated from the ventral branch of the last lumbar spinal nerve, either from the sixth lumbar spinal nerve (L6) or from the seventh (L7), when present, and from the ventral branches of first and second sacral spinal nerves (S1 and S2, respectively), and possibly from the ventral branch of third sacral spinal nerve (S3). The ischiatic nerve provided branches to the superficial gluteal, middle gluteal, accessory gluteal, deep gluteal, gemelli, quadratus femoris, adductor, biceps femoris, semitendinosus and semimembranosus muscles. The tibial and common peroneal nerves were the terminal branches of the ischiatic nerve, originating distally towards the greater trochanter of the femur bone. Wilcoxon’s test (0.05) showed that statistically there were no significant differences between the frequencies of the muscular branches of the ischiatic nerve and the antimeres, regardless of the number of muscular branches.