Perineum

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Perineum

In human anatomy

Human anatomy

Human anatomy, which, with physiology and biochemistry, is a complementary basic medical science is primarily the scientific study of the morphology of the adult human body....
, the perineum is generally defined as the surface region in both males and females between the pubic symphysis

Pubic symphysis

The pubic symphysis is the midline cartilage joint uniting the superior pubic ramus of the left and right pubis . It is located anterior to the urinary bladder and superior to the external genitalia; for females it is above the vulva and for males it is above the penis....
and the coccyx

Coccyx

The coccyx , commonly referred to as the tailbone, is the final segment of the human spine . Comprising three to five separate or fused vertebrae below the sacrum, it is attached to the sacrum by a fibrocartilaginous joint, the sacrococcygeal symphysis, which permits limited movement between the sacrum and the coccyx....
. The perineum is the region of the body inferior to the pelvic diaphragm and between the legs. It is a diamond-shaped area on the inferior surface of the trunk which includes the anus

Anus

The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to expel feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest, such as coprolite ; food material after all the nutrients have b...
and, in females, the vagina

Vagina

The vagina is a fibromuscular cylinder tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles....
. Its definition varies: it can refer to only the superficial structures in this region, or it can be used to include both superficial and deep structures.

The perineum corresponds to the outlet of the pelvis.

The anogenital distance is a measure of male feminisation measuring the distance between the anus

Anus

Penis

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Encyclopedia

In human anatomy

Human anatomy

Pubic symphysis

Coccyx

Anus

Vagina

Anus

Penis

The penis is an external sex organ of certain biologically male organisms, in both vertebrates and invertebrates.The penis is a reproductive organ, technically an intromittent organ, and for Eutheria, additionally serves as the external organ of urination....
. Studies show that the perineum is twice as long in males as in females. Measuring the anogenital distance in neonatal humans has been suggested as a noninvasive method to predict neonatal and adult reproductive disorders.

Boundaries

Its deep boundaries are as follows:

in front: the pubic arch
Pubic arch

The eminences of the lower circumference of the true pelvis are separated by three notches: one in front, the pubic arch, formed by the convergence of the inferior rami of the ischium and pubis on either side....
and the arcuate ligament
Arcuate ligament

The term arcuate ligament refers to an arc-shaped ligament. Specifically, it can refer to a variety of ligaments in the human body:* Arcuate ligaments of the diaphragm...
of the pubis
Pubis (bone)

The android pubic bone is the ventral and anterior of the three principal bones composing either half of the pelvis.It is covered by a layer of fat, which is covered by the mons pubis....
behind: the tip of the coccyx
Coccyx

The coccyx , commonly referred to as the tailbone, is the final segment of the human spine . Comprising three to five separate or fused vertebrae below the sacrum, it is attached to the sacrum by a fibrocartilaginous joint, the sacrococcygeal symphysis, which permits limited movement between the sacrum and the coccyx....
on either side: the inferior rami of the pubis
Inferior pubic ramus

The inferior pubic ramus is thin and flattened. It passes lateralward and downward from the medial end of the superior ramus; it becomes narrower as it descends and joins with the inferior ramus of the ischium below the obturator foramen....
and Ischium, and the sacrotuberous ligament
Sacrotuberous ligament

The sacrotuberous ligament is situated at the lower and back part of the pelvis. It is flat, and triangular in form; narrower in the middle than at the ends....

In Alfred Kinsey's 1967 report, he concluded that the perineum was one of the 6 key erogenous zone

Erogenous zone

An Erogenous zone is an area of the human body that has heightened sensitivity and stimulation of which normally results in human sexual response....
s for males.

Triangles

A line drawn transversely across in front of the ischial tuberosities

Tuberosity of the ischium

Posteriorly, the Superior ramus of the ischium of the ischium forms a large swelling, the tuberosity of the ischium .It marks the lateral boundary of the pelvic outlet....
divides the space into two triangles:

Name	Location	Contents >- \| Urogenital triangle Urogenital triangle The urogenital triangle is the anterior part of the perineum. In females, it contains the vagina and associated parts of the external genitalia....	the anterior triangle	in females, contains the vagina Vagina The vagina is a fibromuscular cylinder tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles.... \|- \| Anal triangle Anal triangle The anal triangle is the posterior part of the perineum. It contains the anal canal....	the posterior triangle	contains the anus Anus The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to expel feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest, such as coprolite ; food material after all the nutrients have b...

Perineal fascia

The terminology of the perineal fascia

Fascia

Fascia , pl. fas?ci?ae , adj. fascial is the soft tissue component of the connective tissue system that permeates the human body....
can be confusing, and there is some controversy over the nomenclature. This stems from the fact that there are two parts to the fascia, the superficial and deep parts, and each of these can be subdivided into superficial and deep parts.

The layers and contents are as follows, from superficial to deep:

1) Skin
Skin

The skin is the outer covering of the body, also known as the epidermis. It is the largest organ of the integumentary system made up of multiple layers of epithelial biological tissue, and guards the underlying muscles, bones, ligaments and organ s....

2) superficial perineal fascia: Subcutaneous tissue divided into two layers: (a) A superficial fatty layer, and (b) Colles' fascia, a deeper, membranous layer.

3) deep perineal fascia and muscles:

superficial perineal pouch Superficial perineal pouch The superficial perineal pouch is a compartment of the perineum....	Contains superficial perineal muscles: transversus perinei superficialis Transversus perinei superficialis muscle The Transversus perinei superficialis is a narrow muscular slip, which passes more or less transversely across the perineal space in front of the anus.... , bulbospongiosus Bulbospongiosus muscle Bulbospongiosus is one of the superficial muscles of the perineum. It has a slightly different origin, insertion and function in males and females.... , ischiocavernosus Ischiocavernosus muscle The ischiocavernosus muscle is a muscle just below the surface of the perineum, present in both men and women.... \|- \| inferior fascia of urogenital diaphragm Urogenital diaphragm Older texts have asserted the existence of an "urogenital diaphragm", which was described as a layer of the pelvis that separates the deep perineal sac from the upper pelvis, lying between the inferior fascia of the urogenital diaphragm and superior fascia of the urogenital diaphragm.... , or perineal membrane Perineal membrane The perineal membrane is an anatomical term for a fibrous biological membrane in the perineum. The term "inferior fascia of urogenital diaphragm", used in older texts, is considered equivalent to the perineal membrane....	A membranous layer of the deep fascia Deep fascia Deep fascia is a layer of fascia which can surround individual muscles, and divide groups of muscles into compartments.Examples include:* Fascia lata... . \|- \| deep perineal pouch Deep perineal pouch The deep perineal pouch is an anatomical term that refers to the space enclosed in part by the perineum, and located superior to the perineal membrane....	Contains the deep perineal muscles: transversus perinei profundus Transversus perinei profundus muscle The Transversus perinei profundus arises from the inferior rami of the ischium and runs to the median line, where it interlaces in a tendinous raph? with its fellow of the opposite side.... , sphincter urethrae membranaceae Sphincter urethrae membranaceae muscle The external sphincter muscle of urethra surrounds the whole length of the membranous portion of the urethra, and is enclosed in the fasci? of the urogenital diaphragm.... \|- \| superior fascia of the urogenital diaphragm Superior fascia of the urogenital diaphragm The superior fascia of the urogenital diaphragm is continuous with the obturator fascia and stretches across the pubic arch.If the obturator fascia be traced medially after leaving the Obturator internus muscle, it will be found attached by some of its deeper or anterior fibers to the inner margin of the pubic arch, while its superficial or...	Considered hypothetical by some modern anatomists, but still commonly used to logically divide the contents of the region.

4) fascia and muscles of pelvic floor
Pelvic floor

The pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus, and associated connective tissue which span the area underneath the pelvis....
(levator ani
Levator ani

The Levator ani is a broad, thin muscle, situated on the side of the pelvis.It is attached to the inner surface of the side of the lesser pelvis, and unites with its fellow of the opposite side to form the greater part of the floor of the pelvic cavity....
, coccygeus)

Areas of the perineum

The region of the perineum can be considered a distinct area from pelvic cavity, with the two regions separated by the pelvic diaphragm. The following areas are thus classified as parts of the perineal region:

perineal pouches: superficial and deep (see above for details)
Ischioanal fossa - a fat filled space at the lateral sides of anal canal. It is bounded laterally by obturator internus muscle, medially by pelvic diaphragm and anal canal. Its base is the skin.

Anal canal
Anal canal

The anal canal is the terminal part of the large intestine.It is situated between the rectum and anus, below the level of the pelvic diaphragm....
Pudendal canal
Pudendal canal

The pudendal canal is an anatomical structure in the pelvis through which the internal pudendal artery, internal pudendal veins, and the pudendal nerve pass....
- contains internal pudendal artery
Internal pudendal artery

The internal pudendal artery is an artery that branches off the internal iliac artery, providing blood to the external genitalia.The internal pudendal artery is the terminal branch of the anterior trunk of the internal iliac artery....
and the pudendal nerve
Pudendal nerve

The pudendal nerve is a somatic nerve in the pelvic region that innervates the external genitalia of both sexes, as well as sphincters for the urinary bladder and the rectum....
.

Perineum

Boundaries

Triangles

Perineal fascia

Areas of the perineum

Additional images

See also

External links