Perineum: anal & urogenital triangles Flashcards
what is the anal triangle?
the posterior half of the perineum
what is the anal triangle bounded by?
the coccyx, sacrotuberous ligaments and an imaginary line between the ischial tuberosities
components of the anal triangle?
Anal aperture
External anal sphincter muscle
Two ischioanal fossae
what is the anal aperture?
the opening of the anus
what is the External anal sphincter muscle
voluntary muscle responsible for opening and closing the anus
what are the Two ischioanal fossae?
paces located laterally to the anus
where is the anal aperture located?
located centrally in the triangle with the ischioanal fossae either side
what do the ischioanal fossae contain?
fat and connective tissue
what is the function of the ischioanal fossae?
aid expansion of the anal canal during defecation
where do the ischioanal fossae extend?
extend from the skin of the anal region inferiorly to the pelvic diaphragm superiorly
what does the urogenital triangle comprise of?
the anterior half of the perineum
what is the urogenital triangle bounded by?
the pubic symphysis, ischiopubic rami, and an imaginary line between the two ischial tuberosities
what are the urogenital triangle associated with?
the structures of the urogenital system – the external genitalia and urethra
brief structure of the urogenital triangle?
complex, with a number of fascial layers and pouches
what is addition in the urogenital triangle that is not present in the anal triangle?
the urogenital triangle has an additional layer of strong deep fascia, known as the perineal membrane
what does the perineal membrane contain?
pouches on its superior and inferior surfaces
what are the different layers of the urogenital triangle? (deep to superficial)
Deep perineal pouch Perineal membrane Superficial perineal pouch Deep perineal fascia Superficial perineal fascia Skin
what is the deep perineal pouch?
A potential space between the pelvic floor superiorly, and the perineal membrane inferiorly
what does the deep perineal pouch contain?
part of the urethra and the external urethral sphincter
what else is contained within the deep perineal pouch in males?
the bulbourethral glands and the deep transverse perineal muscles
what is the perineal membrane?
A layer of tough fascia
what is the perineal membrane perforated by?
the urethra and vagina
what is the role of the perineal membrane?
to provide attachment for the muscles of the superficial external genitalia, and to help support the pelvic viscera
what is the superficial perineal pouch?
A potential space between the perineal membrane superiorly, and the perineal fascia inferiorly
what does the superficial perineal pouch contain?
contains the erectile tissues that form the penis and clitoris, and three muscles
what are the 3 muscles contained within the superficial perineal pouch?
the ischiocavernosus, bulbospongiosus and superficial transverse perineal muscles
what else is located within the superficial perineal pouch aside from the erectile tissues that form the penis and clitoris, and three muscles?
The greater vestibular glands (Bartholin’s glands) are also located in the superficial perineal pouch
what is the deep perineal fascia?
Fascia covering the superficial perineal muscles
what is the superficial perineal fascia continuous with?
continuous with the superficial fascia of the abdominal wall
how can the superficial perineal fascia be divided?
into superficial and deep layers
what is the superficial layer of the superficial perineal fascia like in structure?
fatty in structure
what does the superficial layer of the superficial perineal fascia form in women?
the labia majora and mons pubis in women
which structures open out onto the skin?
The urethral and vaginal orifices open out onto the skin
