An unorthodox innervation of the gluteus maximus muscle and other associated variations: A case report

Abstract

Knowledge of peripheral nerve morphology, location, and variation is important for facilitating appropriate diagnosis and intervention. We present a unique case of absence of the inferior gluteal nerve and high division of the sciatic nerve. In this instance, the common peroneal nerve was found piercing the piriformis muscle and emerging distally in the form of two trunks: thin medial and thick lateral. The medial trunk presented an interesting course, supplying the gluteus maximus muscle before joining the lateral trunk to form the common peroneal nerve. Additionally, the arteria nervi ischiadisci was also observed accompanying and supplying the tibial nerve passing inferior to the piriformis. These variations are important for clinicians and surgeons for some radiological diagnoses and surgical procedures in the lower limb.

A Highly Unusual Source and Course of the Inferior Gluteal Nerve With Related Variations: A Case Report

“…One review showed that the IGN traverses superior to the PM in 0.1-4.4% of individuals [ 6 ]. The present case, like others, describes an instance where the nerve pierces the PM directly [ 7 , 8 ]; another case describes its complete absence [ 5 ]. Notably, these variants of the IGN appear to be strongly associated with ipsilateral splitting of the SN by the PM, possibly because these abnormalities have a shared embryological origin [ 5 , 7 , 8 ].…”

“…Sumalatha et al (2022) reported a case of an SN with a high division (i.e. the CFN and TN descended parallel to and independently of each other), and the IGN being absent [ 5 ]. They found that the CFN provided motor innervation to the GMax muscle in place of the missing IGN.…”

“…Variants of the proximal IGN, particularly in relation to the PM, have not been thoroughly described. In the extant literature, few studies have reported variants ranging from total absence of the nerve [ 5 ] to it following atypical courses either above [ 6 ] or through [ 7 , 8 ] the muscle. Herein, we describe an unusual cadaveric case illustrating an atypical origin of the IGN.…”