Which space is described as the space lateral to the anal canal within the anal triangle?

Which space is described as the space lateral to the anal canal within the anal triangle?

• A. Ischiorectal fossa
• B. Retrovesical space
• C. Vestibular bulb
• D. Psoas compartment

Answer: (A)

The space lateral to the anal canal within the anal triangle is the ischiorectal (ischioanal) fossa. This fat-filled recess sits on each side of the anal canal, with the medial wall formed by the external anal sphincter and lower part of the anal canal, and the lateral wall bounded by the obturator internus muscle and its fascia. Its roof is the pelvic diaphragm, and its floor is the skin of the perineum. The fossa contains the inferior rectal vessels and nerves and is a common site for infections to spread due to its loose connective tissue and continuous fascial planes. The other spaces mentioned do not lie in the anal triangle: the retrovesical space lies between the bladder and rectum, the vestibular bulb is erectile tissue in the female vestibule, and the psoas compartment surrounds the psoas muscle in the pelvis.

The space lateral to the anal canal within the anal triangle is the ischiorectal (ischioanal) fossa. This fat-filled recess sits on each side of the anal canal, with the medial wall formed by the external anal sphincter and lower part of the anal canal, and the lateral wall bounded by the obturator internus muscle and its fascia. Its roof is the pelvic diaphragm, and its floor is the skin of the perineum. The fossa contains the inferior rectal vessels and nerves and is a common site for infections to spread due to its loose connective tissue and continuous fascial planes. The other spaces mentioned do not lie in the anal triangle: the retrovesical space lies between the bladder and rectum, the vestibular bulb is erectile tissue in the female vestibule, and the psoas compartment surrounds the psoas muscle in the pelvis.