P.S. Measurements-total breadth of both the fossae= 5cm

1. JULIT MATHEW
ROLL NO. 86

2. oIschioanal fossa
oWedge-shaped, fat-filled space
o Lateral to the anal canal below the pelvic
diaphragm
oThe two fossae communicate behind the
anal canal.

3. o Base-skin over the anal region of the
perineum
o Apex-directed upward and laterally.
o Measurements-
5cm-5cm-5cm

5. oLateral: Fascia covering the
obturator internus muscle and
ischial tuberosity.
oMedial: Fascia covering the
levator ani muscle and
external anal sphincter.
oPosterior: Sacrotuberous
ligament, on the posterior
surface of which is gluteus
maximus.

7. o Anterior: Posterior border
of the perineal membrane.
oFloor: Perineal skin.
oRoof: Meeting point of the
fascia covering obturator
internus and inferior
fascia of the pelvic
diaphragm.

8. Anterior Recess :Anteriorly
above Urogenital Diaphragm
Posterior Recess :Posteriorly
deep to Sacrotuberous ligament
Horseshoe-shaped Recess :
Connects the two fossa behind
the anal canal

10. Perianal space
o Subcutaneous space on either sides of Anal orifice
o Bounded above-Perianal fascia , below-Perianal skin
PERIANAL FASCIA
o Fibrous septum
o Extends from White line of Hilton (medially) to Pudendal Canal (laterally)
o Perianal space is divided into compartments by fibroelastic septa.
o The fat in here is tightly arranged in small loculi.
o Infection – perianal abscess-painful

12.  Ischioanal space
 Large and deep
 Fat here is arranged in large loculi,formed by incomplete
delicate septa
LUNATE FASCIA
 Arches over Ischioanal fat
 Begins laterally at the pudendal canal ,merges medially
with fascia covering deep part of External anal sphincter.
Fascia divides the space into :
Suprategmental space and Tegmental space

13. o Pudendal canal(Alcock’s canal)
 Fascial canal present in the lateral wall of the ischiorectal fossa about 1
inch (2.5 cm) above the ischial tuberosity
 Extends from the lesser sciatic foramen to the posterior limit of the deep
perineal pouch
 The pudendal canal is formed either by the splitting of the obturator
fascia or by separation between the fascia lunata and the obturator
fascia.
CONTENTS
 1. Pudendal nerve which divides within the canal into the dorsal nerve
of penis and the perineal nerve.
 2. Internal pudendal vessels

14.  Ischioanal pad of fat
 Inferior rectal nerve and vessels- pass through the fossa from lateral to
medial side. They arch upwards above the fat to supply mucous
membrane, External sphincter, skin around the anus.
 Pudendal canal with its contents. The canal lies along the lateral wall of
the fossa.
 Posterior scrotal(males) or posterior labial(females) nerves and vessels.
They cross the Anterolateral part of the fossa and enter the urogenital
triangle.
 Perineal branch of S4 nerve. It enters the posterior angle of the fossa and
runs over the levator ani to the external anal sphincter.
 Perforating cutaneous branches of nerves S2,S3.They appear at the lower
border of the gluteus maximus, in the posterior part of the fossa

16. ISCHIORECTAL ABSCESS

17.  HIATUS OF SCHWALBE

18. THANK YOU