ischioanal fossa (ischiorectal fossa Velpeau fossa)

Introduction

Structre:

• large fascia-lined, wedge shaped spaces between the skin of the anal region & the pelvic diaphragm (seen around the wall of the anal canal)
• wide inferiorly & narrow superiorly, fossae are filled with fat & loose connective tissue

Communication:

• by means of the deep postanal space over the anococcygeal ligament.

Boundaries:

• medially by the levator ani muscle
• laterally by the ischium & the inferior part of the obturator internus, covered with obturator fascia
• posteriorly by the gluteus maximus muscle lying superficial to the sacrotuberous ligament
• anteriorly by the perineal membrane

Complications

• herniation into the rectum results in ischiorectal hernia

More general terms

• fossa

Additional terms

• perineum