Ischio anal fossa

Boundaries

• 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

Contents

• 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