The anal triangle is the posterior part of the
perineum
The perineum (: perineums or perinea) in placentalia, placental mammals is the space between the anus and the genitals. The human perineum is between the anus and scrotum in the male or between the anus and vulva in the female. The perineum is ...
. It contains the
anus in
mammal
A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...
s.
Structure
The anal triangle can be defined either by its
vertices or its sides.
* ''Vertices''
** one vertex at the
coccyx
The coccyx (: coccyges or coccyxes), commonly referred to as the tailbone, is the final segment of the vertebral column in all apes, and analogous structures in certain other mammals such as horse anatomy, horses. In tailless primates (e.g. hum ...
bone
** the two
ischial tuberosities 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 the i ...
*
Pudendal nerve
*
Internal pudendal artery and
internal pudendal vein
*
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 s ...
* Muscles
**
Sphincter ani externus muscle
**
Gluteus maximus muscle
**
Obturator internus muscle
**
Levator ani muscle
**
Coccygeus muscle
The coccygeus muscle or ischiococcygeus is a muscle of the pelvic floor located posterior to levator ani and anterior to the sacrospinous ligament.
Structure
The coccygeus muscle is posterior to levator ani and anterior to the sacrospinous liga ...
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 and the coccyx
The coccyx (: coccyges or coccyxes), commonly referred to as the tailbone, is the final segment of the vertebral column in all apes, and analogous structures in certain other mammals such as horse anatomy, horses. In tailless primates (e.g. hum ...
.
See also
*
Perineum
The perineum (: perineums or perinea) in placentalia, placental mammals is the space between the anus and the genitals. The human perineum is between the anus and scrotum in the male or between the anus and vulva in the female. The perineum is ...
*
Urogenital triangle
The urogenital triangle is the anterior part of the perineum. In female mammals, it contains the vulva, while in male mammals, it contains the penis and scrotum.
Structure
The urogenital triangle is the area bound by a triangle with one vertex a ...
References
External links
* - "The Female Perineum: Boundaries of the Female Perineum"
* ()
{{Authority control
Perineum
Human surface anatomy