Perineum LO4

4. Describe the location of the ischio-anal fossae, and understand the contents located within.

The ischio-anal fossae compose the majority of the superficial anal triangle, and are located lateral to the anal canal and sphincters. The main content of these fossae is adipose tissue, in addition to pudendal neurovasculature.

Boundaries of the ischio-anal fossa:

    • Anterior: pubic bodies
    • Posterior: gluteus maximus m. and sacrotuberous ligament
    • Medial: external anal sphincter and portions of levator ani m.
    • Lateral: lateral pelvic wall, obturator fascia, and obturator internus m. This includes the pudendal (Alcock’s) canal.

Pudendal (Alcock’s) canal is located within the internal obturator fascia of the lateral wall of the ischio-anal fossa. The pudendal neurovasculature traverses the canal to reach the perineum.