Ischio anal fossa




    • Laterally -The ischium, and inferior part of the obturator internus.

    • Medially – Rectum, and the anal canal, with their associated lavetor ani and sphincter ani muscle.

    • Posteriorly- Sacrotuberous ligament and the overlying gluteus maximus muscle.

    • Anteriorly-Base of the urogenital diaphragm

    • Inferiorly- Skin  and deep fascia of the perineum

    • Apex – Between obturator fascia and lavetor ani



    • Ischiorectal pad of fat

      (+) Transversed by many tough fibrous bands of septa.

      (+) This pad of fat supports the anal canal
      It is readily displaced to allow feces to pass.

    • Internal pudendal vessels, and pudendal nerve

    • Inferior rectal vessels and nerves

    • Perforating branches of S2 and S3

    • Perineal branch of S4