Bassett Collection of Stereoscopic Images of Human Anatomy

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Dissection of male pelvis from a lateral approach

Piriformis muscle and nerve supply, medial view

Image #173-1

KEYWORDS: Muscles and tendons, Peripheral nervous system.

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Dissection of male pelvis from a lateral approach

Piriformis muscle and nerve supply, medial view

The right sacral plexus has been resected to permit a view of the piriformis muscle. The nerves to this muscle (19), derived from the first and second sacral nerves and given off from the adjacent part of the sacral plexus, have been preserved.

1 .	Lateral sacral artery (branch of iliolumbar artery)
2 .	Lumbar branch iliolumbar artery
3 .	Lumbosacral trunk
4 .	Upper pointer: Superior gluteal artery Lower pointer: Body of ilium
5 .	Iliolumbar artery (iliac branch of)
6 .	Obturator nerve
7 .	Iliopsoas muscle
8 .	Upper pointer: Obturator artery (entering obturator canal) Lower pointer: Pubic branch of obturator artery
9 .	Body of pubic bone
10 .	Obturator internus muscle
11 .	Ischium
12 .	Superior gluteal vein
13 .	Sacral nerve I (emerging from anterior (pelvic) sacral foramen)
14 .	Ramus communicans
15 .	Sacral nerve II
16 .	Sacrum (body cut through to expose sacral canal)
17 .	Sympathetic trunk
18 .	Sacrum
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
25 .	Ischial spine
26 .	Nerve to obturator internus muscle