The perineum in humans is the space between the anus and scrotum in the male and between the anus and the vulva in the female. The perineum is the region of the body between the pubic symphysis and the coccyx, including the perineal body and surrounding structures. There is some variability in how the boundaries are defined. The perianal area is a subset of the perineum.
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 female external urethral sphincter and the external anal sphincter. If damaged, most commonly by childbirth, lesions may cause sensory loss or fecal incontinence. The nerve may be temporarily blocked as part of an anaesthetic procedure.
The levator ani is a broad, thin muscle group, situated on either side of the pelvis. It is formed from three muscle components: the pubococcygeus, the iliococcygeus, and the puborectalis.
The ischiocavernosus muscle is a muscle just below the surface of the perineum, present in both men and women.
The bulbospongiosus muscle is one of the superficial muscles of the perineum. It has a slightly different origin, insertion and function in males and females. In males, it covers the bulb of the penis. In females, it covers the vestibular bulb.
The internal pudendal artery is one of the three pudendal arteries that branches off the internal iliac artery, providing blood to the external genitalia.
The external iliac arteries are two major arteries which bifurcate off the common iliac arteries anterior to the sacroiliac joint of the pelvis. They proceed anterior and inferior along the medial border of the psoas major muscles. They exit the pelvic girdle posterior and inferior to the inguinal ligament about one third laterally from the insertion point of the inguinal ligament on the pubic tubercle at which point they are referred to as the femoral arteries. The external iliac artery is usually the artery used to attach the renal artery to the recipient of a kidney transplant.
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.
The perineal artery arises from the internal pudendal artery, and turns upward, crossing either over or under the superficial transverse perineal muscle, and runs forward, parallel to the pubic arch, in the interspace between the bulbospongiosus and ischiocavernosus muscles, both of which it supplies, and finally divides into several posterior scrotal branches which are distributed to the skin and dartos tunic of the scrotum.
The inferior rectal artery is an artery that supplies blood to the lower half of the anal canal.
The perineal nerve is a nerve arising from the pudendal nerve that supplies the perineum.
The internal pudendal veins are a set of veins in the pelvis. They are the venae comitantes of the internal pudendal artery.
The Inferior rectal nerves 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 and veins, toward the anal canal and the lower end of the rectum, and is distributed to the Sphincter ani externus and to the integument (skin) around the anus.
The deep external pudendal artery, is one of the pudendal arteries that is more deeply seated than the superficial external pudendal artery, passes medially across the pectineus and the adductor longus muscles; it is covered by the fascia lata, which it pierces at the medial side of the thigh, and is distributed, in the male, to the integument of the scrotum and perineum, in the female to the labia majora; its branches anastomose with the scrotal branches of the perineal artery.
The perineal membrane is an anatomical term for a fibrous membrane in the perineum. The term "inferior fascia of urogenital diaphragm", used in older texts, is considered equivalent to the perineal membrane.
The deep perineal pouch is the anatomic space enclosed in part by the perineum, and located superior to the perineal membrane.
The urogenital triangle is the anterior part of the perineum. In female mammals, it contains the vagina and associated parts of the external genitalia.
The anal triangle is the posterior part of the perineum. It contains the anal canal.
The following outline is provided as an overview of and topical guide to human anatomy:
The vaginal support structures are those muscles, bones, ligaments, tendons, membranes and fascia, of the pelvic floor that maintain the position of the vagina within the pelvic cavity and allow the normal functioning of the vagina and other reproductive structures in the female. Defects or injuries to these support structures in the pelvic floor leads to pelvic organ prolapse. Anatomical and congenital variations of vaginal support structures can predispose a woman to further dysfunction and prolapse later in life. The urethra is part of the anterior wall of the vagina and damage to the support structures there can lead to incontinence and urinary retention.
