During a total hip replacement through the posterior approach, the surgeon must detach and later repair the short external rotators. Which muscle forms the key landmark for identifying the sciatic nerve in this approach?

• A Piriformis ✓
• B Obturator internus
• C Quadratus femoris
• D Gemellus superior

Explanation

The piriformis muscle is the key landmark in the posterior approach to the hip joint. The sciatic nerve exits the greater sciatic foramen below the piriformis (in 85% of individuals); the common peroneal nerve may exit above piriformis in anatomical variations. During posterior hip approach, surgeons identify the piriformis to avoid sciatic nerve injury. The tendon of piriformis is detached from the greater trochanter and tagged for repair. The short external rotators (obturator internus with gemelli, quadratus femoris) below piriformis are also detached and later repaired to restore posterior capsule support.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.