Exploration of gluteal region and hip

Intrapelvic portions of obturator internus and piriformis muscles, medial view

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Image #181-3

Exploration of gluteal region and hip Intrapelvic portions of obturator internus and piriformis muscles, medial view The pelvic contents have been removed and the sacral plexus on the right side has been cut away to expose the piriformis muscle. The nerves to the piriformis (19), derived from the first and second sacral nerves, have been preserved. The obturator internus (10) has also been dissected with its nerve supply. The insertions of both muscles are visible in the dissections illustrated in views 180-4 and 181-4. 1 . Lateral sacral artery (branch of Iliolumbar artery) 2 . Lumbar branch of iliolumbar artery 3 . Lumbosacral trunk 4 . Upper pointer: Superior gluteal artery Lower pointer: Body of ilium 5 . Iliolumbar artery (iliac branch) 6 . Obturator nerve 7 . Iliopsoas muscle 8 . Upper pointer: Obturator artery (entering obturator canal) Lower pointer: Pubic branch of obturator artery 9 . Body of pubis 10 . Obturator internus muscle 11 . Ischium 12 . Superior gluteal vein 13 . S1 nerve (emerging from posterior sacral foramen) 14 . Ramus communicans 15 . Sacral nerve II 16 . Sacral bone (body cut through to expose sacral canal) 17 . Sympathetic trunk 18 . Sacral bone 19 . Nerve to piriform muscle 20 . Piriform muscle 21 . Inferior gluteal artery 22 . Greater sciatic foramen (piriform muscle passing through) 23 . Coccygeus muscle 24 . Coccyx bone 25 . Ischial spine 26 . Nerve to Obturator internus muscle