The sciatic nerve (SN) is the largest and longest peripheral nerve in the human body. Its anatomical course demonstrates considerable variability, particularly in its relationship with the piriformis muscle (PM). Several bifurcation patterns of the tibial nerve (TN) and common fibular nerve (CFN) have been described and classified into six types (I-VI) to facilitate their identification and prevalence assessment. The present study reports a newly observed and atypical variant of SN division, which, to our knowledge, has not been previously documented in the literature. During routine cadaveric dissection, an unusual configuration of the SN was identified on the left side. The TN passed inferior to the PM, whereas the CFN bifurcated into two distinct branches: a superior branch traversing the fibers of the PM, and an inferior branch accompanying the TN beneath the muscle. No such variation was found on the contralateral side. A comprehensive understanding of SN anatomical variations is crucial for improving the precision and outcomes of surgical procedures. Magnetic resonance imaging (MRI) can serve as a valuable tool in preoperative planning by delineating the course and morphology of the SN. Such knowledge aids in diagnosing piriformis syndrome (PS) and helps minimize postoperative neurological complications. Our research team is the first to describe this particular variant of SN bifurcation.
Siwek et al. (Fri,) studied this question.