The Perineum Flashcards
Clinically, the perineum is
…the space between the anus and scrotum in the male and anus and vulva in the female.
The perineum broadly applies to…
…the structures of the outlet of the pelvis, superficial to the levator ani muscle.
The perineum lies ____ and is separated from the pelvic cavity by _____
inferior to the pelvic outlet, the pelvic diaphragm
Boundaries of the perineum
Anterior: Lower edge of symphysis pubis
Posterior: Coccyx
Lateral: Ischial tuberosity
Roof of the perineum
The pelvic floor
Floor of the perineum
Skin and fascia
An imaginary horizontal line between the 2 ichial tuberosities divides perineum into
2 triangles:
Anterior - Urogenital triangle
Posterior - Anal triangle
What is the perineal body?
A fibromuscular mass in the midline of the perineum at the junction between the urogenital triangle and the anal triangle
Location of the perineal body in males
Between the bulb of penis and the anus
Location of the perineal body in females
Between the vagina and anus
Significance of the perineal body
- Attachment: Integral attachment point for components of the urinary and faecal continence mechanism
- Tear resistance: Essential for the integrity of the pelvic floor, particularly in females as rupture during delivery predisposes the woman to prolapse of the pelvic organs
Attachments of the perineal body
- External anal sphincter
- Bulbospongiosus
- Superficial and deep transverse perineal muscle
- Anterior fibres of the levator ani
- Fibres from external urinary sphincter
Boundaries of the anal triangle
coccyx, sacrotuberous ligaments
Contents of the anal triangle
- Anal aperture
- External anal sphincter muscle
- Ischioanal fossae containing fat
- Pudendal nerve and Internal Pudendal Vessels
- Inferior rectal nerve and vessels
Significance of the ischioanal fossae
They contain fat and connective tissue, which allow for expansion of the anal canal during defecation.
The urogenital triangle is bounded by
- the pubic symphysis
- ischiopubic rami
The urogenital compartment is divided into…
Superficial perineal
Deep perineal
Roof of the superficial perineal membrane
Perineal membrane
Floor of the superficial perineal membrane
Colle’s fascia
The perineal membrane is…
…a dense, fibromuscular, triangular sheet in the anterior half of pelvic outlet
Significance of the pelvic membrane
- It provides attachment for the muscles of the external genitalia.
- Counteracts effects of gravity
Difference between perineal membrane in male and female
Complete sheet in males, perforated by the urethra and the vagina in the female
Attachments of the perineal membrane
Urethra
Vagina
Perineal body
Contents of the male superficial compartment of the urogenital triangle
Bulbospongiosus muscle
Superficial transverse perineal muscle
Perineal body
Contents of the female superficial compartment of the urogenital triangle
- Erectile tissues that form the clitoris
- the ischiocavernosus
- bulbospongiosus
- superficial transverse perineal muscles
- greater vestibular glands (Bartholin’s glands
Contents of the female deep compartment of the urogenital triangle
- urethra
- external urethral sphincter
- vagina
Contents of the male deep compartment of the urogenital triangle
- urethra
- external urethral sphincter
- bulbourethral glands
- deep transverse perineal muscles
Blood supply of the perineum
Branches of the internal pudendal artery
