Ischiorectal Fossa

Ischiorectal fossa, also known as the ishioanal fossa, is a wedge shaped space located on each side of the anal canal. The base of this wedge-shaped fossa is superficial and is formed by the skin. On the other hand, the apex lies deep and is formed by the junction of medial and lateral walls.

The medial wall is formed by the sloping levator ani muscle and the anal canal. The lateral wall is formed by the lower part of the obturator internus muscle, which is covered with pelvic fascia.

Contents of ischiorectal fossa:

Ischiorectal fossa has the following important contents:

  • Fat: The fossa is filled mostly with dense fat that supports the anal canal. The fat is important because it allows the distention of anal canal during defecation.
  • Pudendal canal: On the lateral wall of the ischiorectal fossa, there is a fascial canal known as the pudendal canal. It houses the pudendal nerve and the internal pudendal blood vessels.
  • Inferior rectal vessels and nerves: These cross the ischiorectal fossa to reach the anal canal.