The anal triangle is the posterior part 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), inclu ...
. It contains the
anal canal
The anal canal is the part that connects the rectum to the anus, located below the level of the pelvic diaphragm. It is located within the anal triangle of the perineum, between the right and left ischioanal fossa. As the final functional segm ...
.
Structure
The anal triangle can be defined either by its
vertices or its sides.
* ''Vertices''
** one vertex at the
coccyx bone
** the two
ischial tuberosities
The ischial tuberosity (or tuberosity of the ischium, tuber ischiadicum), also known colloquially as the sit bones or sitz bones, or as a pair the sitting bones, is a large swelling posteriorly on the superior ramus of the ischium. It marks t ...
of the
pelvic bone
* ''Sides''
**
perineal membrane (posterior border of perineal membrane forms anterior border of anal triangle)
** the two
sacrotuberous ligaments
Contents
Some components of the anal triangle include:
[Daftary, Shirish; Chakravarti, Sudip (2011). Manual of Obstetrics, 3rd Edition. Elsevier. pp. 1-16. .]
*
Ischioanal fossa
*
Anococcygeal body
*
Sacrotuberous ligament
*
Sacrospinous ligament
The sacrospinous ligament (small or anterior sacrosciatic ligament) is a thin, triangular ligament in the human pelvis. The base of the ligament is attached to the outer edge of the sacrum and coccyx, and the tip of the ligament attaches to th ...
*
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 ...
*
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 ...
and
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 puden ...
*
Anal canal
The anal canal is the part that connects the rectum to the anus, located below the level of the pelvic diaphragm. It is located within the anal triangle of the perineum, between the right and left ischioanal fossa. As the final functional segm ...
* Muscles
**
Sphincter ani externus muscle
**
Gluteus maximus muscle
**
Obturator internus muscle
**
Levator ani muscle
**
Coccygeus muscle
Additional images
Image:Gray320.png, Articulations of pelvis. Posterior view.
Image:Gray542.png, The superficial branches of the internal pudendal artery.
Image:Gray1077.png, The posterior aspect of the rectum exposed by removing the lower part of the sacrum
The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30.
The sacrum situates at the upper, back part ...
and the coccyx.
See also
*
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), inclu ...
*
Urogenital triangle
References
External links
* - "The Female Perineum: Boundaries of the Female Perineum"
* ()
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Perineum
Human surface anatomy