Ischiorectal Fossa

Question 1

Site

Answer 1

In perineum anal triangle on each side of anal canal

Question 2

Boundries

Answer 2

1. Wedge shaped
2. 4 walls
3. Apex
4. Base

Question 3

Apex

Answer 3

Levator ani origin from obturator fascia

Question 4

Apex

Answer 4

Levator ani origin from obturator fascia

Question 5

Floor (base)

Answer 5

Perineum skin and fascia

Question 6

Medial wall

Answer 6

1. Upper 2/3:
   - Sloping
   - Levator ani muscle
2. Lower 1/3:
   - Vertical
   - External anal sphincter

Question 7

Lateral wall

Answer 7

1. Obturator internus muscle lower part and its fascia
2. Fascia lower part splits forming pudendal canal (Alcock’s canal) which encloses pudendal nerve and internal pudendal vessels

Question 8

Anterior wall

Answer 8

Perineal membrane posterior border with superficial and deep transverse perineal muscles

Question 9

Posterior wall

Answer 9

Sacrotuberous ligament overlapped by gluteus maximus lower fibers

Question 10

Content

Answer 10

1. Semi- liquid fat
2. Inferior rectal vessels
3. Inferior rectal nerve
4. Perineal artery
5. Posterior scrotal (in male) or labial (in female)
6. Perineal branch of S4 nerve

Question 11

Semi-liquid fat

Answer 11

Allow anal canal distension during defecation

Question 12

Inferior rectal vessels

Answer 12

1. The artery arises from internal pudendal artery in pudendal canal
2. Crosses fossa from lateral to medial reaching anal canal
3. The vein accompanies the artery to end in internal pudendal vein

Question 13

Inferior rectal nerve

Answer 13

1. From pudendal nerve in pudendal canal
2. It crosses fossa from lateral to medial
3. Supply:
   - External anal sphincter
   - Levator ani
   - Skin around anus

Question 14

Perineal artery

Answer 14

1. From internal pudendal artery in pudendal canal anterior end
2. Pierces its medial wall entering ischiorectal fossa
3. Then pierces perineal membrane entering superficial perineal pouch

Question 15

Posterior scrotal or labial nerves

Answer 15

1. From perineal nerve near pudendal canal anterior end
2. Supply scrotum or labia majora

Question 16

Perineal branch of S4 nerve

Answer 16

1. Pierces coccygeus
2. Enters ischiorectal fossa posterior part
3. Then passes forwards to supply external anal sphincter and levator ani

Question 17

Applied anatomy

Answer 17

1. Infection may occur in ischiorectal fossa from boils around anus or lesions within anal canal
2. It may open medial in anal canal connection between anal canal and skin around anus is called anal fistula