Ischioanal fossa

Ischioanal Fossa

The Ischioanal Fossa, also known as the Ischiorectal Fossa, is an important anatomical space located in the pelvis. It is a fat-filled space that lies on each side of the anal canal and below the pelvis diaphragm. The ischioanal fossa plays a crucial role in providing room for the expansion of the anal canal during defecation, as well as housing various blood vessels, nerves, and fat.

Anatomy

The ischioanal fossa is pyramid-shaped with its base facing the skin around the anus and its apex pointing towards the origin of the levator ani muscle. The fossa is bordered medially by the external anal sphincter and the levator ani muscle, laterally by the ischium bone and the obturator internus muscle, anteriorly by the perineal body, and posteriorly by the sacrotuberous ligament and the gluteus maximus muscle.

Contents

The ischioanal fossa contains:

• Fat: The primary content, which serves as a cushion and provides flexibility.
• Pudendal nerve: This nerve runs through the fossa, providing sensory and motor innervation to the pelvic region.
• Blood vessels: Including branches of the internal pudendal artery and vein.
• Lymphatics: Lymph vessels and nodes involved in the drainage of the pelvis and perineum.

Clinical Significance

The ischioanal fossa is of particular interest in medicine due to its involvement in various conditions:

• Abscesses: Infections can lead to the formation of an abscess in the ischioanal fossa, which may require surgical drainage.
• Anesthesia: The pudendal nerve can be blocked in this region to provide anesthesia for childbirth and some surgical procedures.
• Injuries: Trauma to the pelvis can involve the ischioanal fossa, affecting the structures contained within it.

Surgical Considerations

Knowledge of the ischioanal fossa's anatomy is essential for surgeries involving the rectum, anus, and perineum. Procedures such as the excision of rectal tumors, repair of anal fistulas, and the drainage of abscesses necessitate careful navigation of this space to avoid damage to the pudendal nerve and other vital structures.

See Also

• Anal canal
• Pelvis
• Pudendal nerve
• Levator ani