Case report: absence of the right piriformis muscle in a woman

Erich Brenner,Massimiliano Tripoli,Adriana Cordova,Elia Scavo

doi:10.1007/s00276-018-02176-6

Abstract

We report a very rare case of a unilaterally absent piriformis muscle in a 60 year old woman. Accompanying variations comprised a common gluteal artery (instead of two distinct superior and inferior gluteal arteries), and an absent gemellus inferior muscle. The contralateral left side showed a normally developed piriformis muscle. In hominoids, the piriformis is constant, but is regularly missing in several other vertebrates. The piriformis muscle is an anatomical landmark for ultrasound investigations and ultrasound-guided interventions in the deep gluteal region such as a superior gluteal nerve block or even a sacral plexus block, also for any surgical approach such as total hip arthroplasty. A missing piriformis muscle therefore affects the orientation in the deep gluteal region and therefore the identification of the targeted structures.

Highlights

The piriformis muscle is clinically well known for the compression of the sciatic nerve, the piriformis syndrome or deep gluteal syndrome [11].Related on this pathology, a vast amount of studies investigated the relationship between the piriformis muscle and the sciatic nerve, reporting the variability of the piriformis muscle mainly according to the classification by Beaton and Anson [3]
A vast amount of studies investigated the relationship between the piriformis muscle and the sciatic nerve, reporting the variability of the piriformis muscle mainly according to the classification by Beaton and Anson [3]
Macalister cites case reports by Otto and Budge: in the subject dissected by Budge the lower limb was deformed [9], and in the specimen dissected by Otto the gemellus superior was very large [9]

Summary

Introduction

The piriformis muscle is clinically well known for the compression of the sciatic nerve, the piriformis (muscle) syndrome or deep gluteal syndrome [11].Related on this pathology, a vast amount of studies investigated the relationship between the piriformis muscle and the sciatic nerve, reporting the variability of the piriformis muscle mainly according to the classification by Beaton and Anson [3]. Keywords Piriformis muscle · Anatomical variation · Deep gluteal region · Common gluteal artery · Gemellus inferior muscle · Anatomical variation The piriformis muscle is clinically well known for the compression of the sciatic nerve, the piriformis (muscle) syndrome or deep gluteal syndrome [11].

Results

Conclusion