Anatomical study of the intrapelvic portion of ischiatic nerve in fetuses in crossbred zebu cattle

Abstract

The sciatic nerve is the largest of all nerves of the body. It emerges from the pelvic cavity through the major sciatic foramen as a wide, flat and brownish cord. It extends caudally and ventrally over the distal and lateral part of the pelvic broad ligament. There are several experimental and clinical evidences supporting that the majority of injuries affecting the sciatic nerve in bovines are associated with its 6th lumbar nerve. This study analyzed the sciatic nerve origin and topography by means of dissection in 33 crossbred zebu fetuses. The sciatic nerve originates from the ventral branches of the 5th and 6th lumbar nerves and 1st, 2nd and 3rd sacral nerves. The most frequent origin of the sciatic nerve is represented by the ventral branch of the 6th lumbar nerve and 1st and 2nd sacral nerves (100%). The most conspicuous participation in the sciatic nerve formation is from the 6th lumbar nerve and 1st sacral nerve (39.4%), followed only by the 1st sacral nerve in 33% and from the association of the 1st and 2nd sacral nerves in 18.18%. The sciatic nerve shows close apposition in the sacral ventral face and as to the 5th and 6th lumbar nerve ventral roots. In general, the obtained results concerning the nerve origin and its topography do not demonstrate any discrepancy when compared to data from the literature regarding European cattle.