GABRIELLI, Carla, OLAVE, Enrique, MANDIOLA, Eduardo et al.
Abstract : The inferior gluteal nerve, branch of the sacral plexus, leaves the pelvis and passes usually below of the piriformis muscle. The sciatic nerve also comes from this plexus and can present distinct relationships with the mentioned muscle, among these ones it is found the one related to the high division of the nerve. However, the studies that correlates this division with the course of the inferior gluteal nerve and its relationship with the piriformis muscle are scarce. In order to verify a possible association between these anatomical structures, we dissected 80 gluteal regions of adult Brazilian cadavers. Two types of variations were found between the sciatic nerve and the piriformis muscle. The common fibular nerve pierced the muscle and the tibial nerve passed below of its inferior margin in 9 cases (11,2 %), corresponding to the type I; in 6 of these cases the trunk of the inferior gluteal nerve passed through the muscle and in just 3 cases, only a portion perforated the muscle. The type II was observed in 2 cases (2,5 %), corresponding to the same individual, in this type the common fibular nerve passed over the superior margin and the tibial nerve below of the inferior margin of the piriformis muscle. In the rigth side, the trunk of the inferior gluteal nerve passed below of the inferior margin of the muscle; in the left side, it is found only a portion of the nerve originated from the common fibular nerve and the other portion passed below the inferior margin of the muscle. The course of the inferior gluteal nerve through the piriformis muscle could be related to the gluteal atrophy observed in the patients with the "piriformis syndrome
Keywords: Anatomy; Sacral plexus; Sciatic nerve; Gluteal region
Rev. chil. anat., 1997, vol.15, no.1, p.79-83. (Full text available in Spanish).