What is the anal triangle?

The anal triangle is the posterior portion of the perineum. It contains the anal canal and the paired ischiorectal fossae.

What are the boundaries of the anal triangle?

Its boundaries are: Anterior: Horizontal line between ischial tuberosities. Lateral: Ischial tuberosities. Inferolateral: Sacrotuberous ligaments. Posterior: Coccyx.

What structures are found in the anal triangle?

Key contents include the anal canal, the ischiorectal fossae, inferior rectal nerves and vessels, the perineal branch of S4, and posterior scrotal/labial nerves and vessels.

What is the ischiorectal fossa and what is its function?

The ischiorectal fossa is a wedge-shaped, fat-filled space on either side of the anal canal. Its primary functions are to allow expansion of the anal canal during defecation and to provide a cushion.

What is the pudendal nerve and what does it supply?

The pudendal nerve is the chief nerve of the perineum. Its major branches supply the anal sphincter and perianal skin, the perineal muscles and skin, and the external genitalia.

What is a pudendal nerve block and when is it used?

A pudendal nerve block is a procedure where local anesthetic is injected near the ischial spine. It is used to provide perineal anesthesia during childbirth or perineal surgery.

What is an ischiorectal abscess and why is it clinically significant?

An ischiorectal abscess is a painful infection in the fat-filled ischiorectal fossa. It is significant because the area is poorly vascularized, which can lead to complications like a fistula-in-ano.

Anal Triangle – Ischioanal Fossa & Pudendal Canal

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