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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

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Image #173-7
Bassett Image
Diagram Image
Legend Image
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