Anatomy of the ischioanal (or ischiorectal) fossa

Summary

This video explores the anatomy of the ishq rectal fossa and its surrounding structures. The ishq rectal fossa, a wedge-shaped space near the anal canal, contains fatty tissue and plays a role in anal canal dilation during defecation. It is bordered by muscles such as the obturator internus and levator ani, with important structures like the pudendal canal running through it. The perianal space, located around the anal orifice, houses vital structures including the external anal sphincter and hemorrhoidal plexus. The video also covers the anatomy of the pudendal canal, highlighting its contents like the pudendal nerve and arteries.

Takeaways

• 😀 The ishq-rectal fossa is a wedge-shaped space located on either side of the anal canal and beneath the pelvic diaphragm.
• 😀 This fossa is primarily filled with fatty tissue that surrounds the anus and the urogenital hiatus.
• 😀 The two ishq-rectal fossae communicate behind the anal canal and assist in the dilation of the anal canal during defecation.
• 😀 Each ishq-rectal fossa measures about 5 cm in length, width, and slightly more than 5 cm in depth.
• 😀 The lateral wall of the ishq-rectal fossa is formed by the ischium and obturator internus muscle.
• 😀 The medial wall is made up of the levator ani muscle and the external anal sphincter.
• 😀 The posterior boundary is the sacrotuberous ligament, with the gluteus maximus muscle on its posterior surface.
• 😀 The anterior boundary is formed by the posterior border of the perineal membrane.
• 😀 The floor of the fossa is formed by perineal skin, and the roof is created by the fascia covering the obturator internus and the inferior fascia of the pelvic diaphragm.
• 😀 The pudendal canal (also known as Alcock's canal) crosses the lateral margin of the ishq-rectal fossa and contains the internal pudendal artery, veins, and the pudendal nerve.
• 😀 The perianal space is located at the termination of the anal canal, bounded by the perianal fascia above and perianal skin below.
• 😀 The perianal space is subdivided into compartments by fibroelastic septa, and infections here can cause painful perianal abscesses.
• 😀 The contents of the perianal space include the subcutaneous part of the external anal sphincter, external hemorrhoidal venous plexus, and fat.
• 😀 The pudendal canal, located in the lower lateral wall of the ishq-rectal fossa, contains the pudendal nerve, internal pudendal artery, and vein.

Q & A

What is the ischioanal fossa and where is it located?

The ischioanal fossa is a wedge-shaped space situated on either side of the anal canal, below the pelvic diaphragm. It primarily contains fatty tissue surrounding the anus and urogenital hiatus.

What is the main function of the ischioanal fossa?

The ischioanal fossa helps in the dilation of the anal canal during defecation, which is the passage of feces.

What are the dimensions of the ischioanal fossa?

Each ischioanal fossa measures about 5 centimeters in length, 5 centimeters in width, and 5 centimeters or slightly more in depth.

What forms the lateral wall of the ischioanal fossa?

The lateral wall of each fossa is formed by the ischium and the obturator internus muscle.

What forms the medial wall of the ischioanal fossa?

The medial wall is formed by the levator ani muscle and the external anal sphincter.

What anatomical structures bound the ischioanal fossa posteriorly and anteriorly?

Posteriorly, the ischioanal fossa is bounded by the sacrotuberous ligament and the gluteus maximus. Anteriorly, it is bounded by the posterior border of the perineal membrane.

What structures form the roof and floor of the ischioanal fossa?

The floor is formed by the perineal skin, while the roof is formed by the meeting point of the fascia covering the obturator internus and the inferior fascia of the pelvic diaphragm.

What is the pudendal canal and what does it contain?

The pudendal canal, also known as the Alcock canal, is a structure that crosses the lateral margin of the ischioanal fossa. It contains the internal pudendal artery, the internal pudendal veins, and the pudendal nerve.

What is the perianal space and what does it contain?

The perianal space is located around the anal orifice and is bounded by the perianal fascia and perianal skin. It contains the subcutaneous part of the sphincter ani externus muscle, the external hemorrhoidal venous plexus, and fat.

What is the role of the perianal fascia in the perianal space?

The perianal fascia is a fibrous septum that extends from the white line of Hilton medially to the pudendal canal laterally. It helps in dividing the perianal space into various compartments.

How is the perianal space subdivided?

The perianal space is subdivided into multiple compartments by fibroelastic septa, and the fat within this space is tightly arranged into small loculi.

What is the significance of infection in the perianal space?

Infection in the perianal space can lead to perianal abscesses, which are very painful due to the tightly arranged fat and the sensitive structures in the area.

Where is the Alcock canal located and what does it contain?

The Alcock canal, or pudendal canal, is located one inch (2.5 cm) above the ischial tuberosity, extending from the lesser sciatic foramen to the posterior limit of the deep perineal pouch. It contains the pudendal nerve, which divides into the dorsal nerve of the penis and the perineal nerve, as well as the internal pudendal artery and vein.