Bassett Collection of Stereoscopic Images of Human Anatomy

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Dissection of anal triangle and ischiorectal fossae

Course of internal pudendal artery and pudendal nerve in pudendal canal; muscles of pelvic diaphragm

Image #173-7

KEYWORDS: Muscles and tendons, Peripheral nervous system, Vasculature.

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Dissection of anal triangle and ischiorectal fossae

Course of internal pudendal artery and pudendal nerve in pudendal canal; muscles of pelvic diaphragm

The sacrotuberous ligament has been cut away on the left to expose the course of the internal pudendal artery and the pudendal nerve as these structures pass posterior to the ischial spine (8) to enter the pudendal canal (15). The lunate fascia has been reflected to open the entire length of the pudendal canal which extends anteriorly to the posterior border of the urogenital diaphragm. The latter is obscured by the muscles that occupy the superficial perineal space.

1 .	Thoracolumbar fascia
2 .	Erector spinae muscle
3 .	Gluteus maximus muscle
4 .	Gluteus medius muscle
5 .	Piriform muscle
6 .	Upper pointer: Sacrotuberous ligament (cut off) Lower pointer: Coccygeus muscle
7 .	Inferior gluteal nerve
8 .	Upper pointer: Internal pudendal artery (crossing ischial spine) Middle pointer: Dorsal nerve of the penis Lower pointer: Perineal nerve
9 .	Posterior femoral cutaneous nerve
10 .	Upper pointer: Sciatic nerve Lower pointer: Quadratus femoris muscle
11 .	Obturator externus muscle
12 .	Lesser trochanter
13 .	Sacrotuberous ligament (cut off)
14 .	Upper pointer: Inferior rectal nerve Lower pointer: Inferior rectal artery
15 .	Left pointer: Obturator fascia Right pointer: Lunate fascia covering pudendal canal (reflected to open canal)
16 .	Levator ani muscle
17 .	Upper pointer: Anus Lower pointer: External anal sphincter muscle
18 .	Superficial dorsal sacrococcygeal ligament
19 .	Upper pointer: Coccyx (end piece) Lower pointer: Anococcygeal nerve
20 .	Anococcygeal ligament
21 .	Ischial tuberosity
22 .	Sciatic nerve
23 .	Adductor brevis muscle
24 .	Lunate fascia at posterior border of urogenital diaphragm
25 .	Perineal artery
26 .	Ischiocavernosus muscle
27 .	Bulbospongiosus muscle
28 .	Penis