The level of the sciatic nerve division and its relations to the piriform muscle

Abstract

Although very rare, anatomical abnormalities of common peroneal nerve in regard to piriform muscle are still possible.

The sciatic nerve in human cadavers — high division or low formation?

“…While two specimens (1 and 3) from our study appeared to be Beaton and Anson type 3 variation (Fig. 4), in which CFN was passing through the SP and the TN through the IP, these variations were reported by Ugrenovic et al [23] in 1.5% of their cases. In our study, we noted that the two divisions were joining together and forming SN in the upper part of the thigh.…”

“…The incidence of high division of SN, that is, the division of SN above its usual site varies considerably. For instance, the reported incidences of SN division before its exit in the gluteal region vary from 4.0% [23], to 20.9% [17] to 48.0% [7].…”

A Rare Case of Bilateral Supra Piriformis Pelvic Exit of Common Peroneal Nerve: Significance in Pelvic and Hip Surgery

“…Atypical pelvic exit of the sciatic nerve was also observed in the dissection of a human fetus [5]. A detailed systematic review and meta-analysis of the occurrence of anomalous piriformis/sciatic nerve relationships that included 18 studies with over 6062 cadaveric specimens and 7 studies of 130 surgical cases [4] resulted in 6 types of sciatic nerve division (Table 1).…”

Non-formation of the main trunk of the sciatic nerve and unusual relationships to the piriformis muscle

“…A recent study [11] reports a similar incidence of the same variation -9% of the sample. The relative portion of similar Type 2 variations is as low as 2,5% in a study conducted on fetuses (12). However, studies based on a Japanese population report the typical Type 1 anatomy to be present in only 60% of cases, while in the rest numerous variations were described, with Beaton and Anson Type 2 being the most common -34% of extremities (13).…”