Branches of the sacral plexus have been elevated in order to demonstrate the nerve to the quadratus femoris (4) in its course across the posterior surface of the ischium deep to the gemelli and obturator internus muscles.
Inferior gluteal artery
Sacral plexus (elevated)
Parietal pelvic fascia
Nerve to Quadratus femoris muscle
Body of ischium
Gluteus minimus muscle
Sciatic nerve (elevated)
Piriform muscle (cut off close to insertion)
Obturator internus muscle
Obturator externus muscle
Location of quadrate tubercle of femur
Quadratus femoris muscle
Internal pudendal artery
Sacrospinous ligament
Nerve to obturator internus
Inferior rectal artery
Sacrotuberous ligament (cut and reflected medially)
Levator ani muscle
Pudendal nerve
Upper pointer: Pudendal canal Lower pointer: Lunate fascia (reflected to open pudendal canal)