Dissection of anal triangle and ischiorectal fossae

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

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Image #173-7

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