The ischioanal fossa (formerly called ischiorectal fossa) is the fat-filled wedge-shaped space located lateral to the anal canal and inferior to the
pelvic diaphragm
The pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus muscle, and associated connective tissue which span the area underneath the pelvis. The pelvic diaphragm is a muscular partition formed by the le ...
. It is somewhat prismatic in shape, with its base directed to the surface of the
perineum
The perineum in humans is the space between the anus and scrotum in the male, or between the anus and the vulva in the female. The perineum is the region of the body between the pubic symphysis (pubic arch) and the coccyx (tail bone), includi ...
and its apex at the line of meeting of the
obturator and
anal fasciae.
Boundaries
It has the following boundaries:
[ - Ischiorectal fossa is colored yellow]
Contents
The contents include:
* Inside
Alcock's canal
The pudendal canal (also called Alcock's canal) is an anatomical structure in the pelvis through which the internal pudendal artery, internal pudendal veins, and the pudendal nerve pass.
Structure
The pudendal canal is formed by the fascia of the ...
, on the lateral wall
**
internal pudendal artery
The internal pudendal artery is one of the three pudendal arteries. It branches off the internal iliac artery, and provides blood to the external genitalia.
Structure
The internal pudendal artery is the terminal branch of the anterior trunk of ...
**
internal pudendal vein
The internal pudendal veins (internal pudic veins) are a set of veins in the pelvis. They are the venae comitantes of the internal pudendal artery. Internal pudendal veins are enclosed by pudendal canal, with internal pudendal artery and pudenda ...
**
pudendal nerve
The pudendal nerve is the main nerve of the perineum. It carries sensation from the external genitalia of both sexes and the skin around the anus and perineum, as well as the motor supply to various pelvic muscles, including the male or fem ...
* Outside Alcock's canal, crossing the space transversely
**
inferior rectal artery
The inferior rectal artery (inferior hemorrhoidal artery) is an artery that supplies blood to the lower third of the anal canal below the pectinate line.
Structure
The inferior rectal artery arises from the internal pudendal artery as it passes ab ...
**
inferior rectal veins
The lower part of the external hemorrhoidal plexus is drained by the inferior rectal veins (or inferior hemorrhoidal veins) into the internal pudendal vein
The internal pudendal veins (internal pudic veins) are a set of veins in the pelvis. They ...
**
inferior anal nerves
The Inferior rectal nerves (inferior anal nerves, inferior hemorrhoidal nerve) usually branch from the pudendal nerve but occasionally arises directly from the sacral plexus; they cross the ischiorectal fossa along with the inferior rectal artery a ...
** fatty tissue across which numerous fibrous bands extend from side to side allows distension of the anal canal during defecation
See also
*
Anal triangle
References
Additional images
File:Gray407.png, Coronal section of anterior part of pelvis, through the pubic arch. Seen from in front.
File:Gray542.png, The superficial branches of the internal pudendal artery.
External links
*
* - "The Female Perineum: The Ischioanal Fossa"
*
*
* (, )
Diagramat
Emory University
Emory University is a private research university in Atlanta, Georgia. Founded in 1836 as "Emory College" by the Methodist Episcopal Church and named in honor of Methodist bishop John Emory, Emory is the second-oldest private institution of ...
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Perineum