Perineum

1. Perineum
Hamid

2. Definition of Perineum
• The cavity of the pelvis is divided by the pelvic
diaphragm into the main pelvic cavity above
and the perineum below.
• When seen from below with the thighs
abducted, the perineum is diamond shaped
and is bounded anteriorly by the symphysis
pubis, posteriorly by the tip of the coccyx, and
laterally by the ischial tuberosities.

3. Urogenital and Anal triangle

5. boundaries of the perineum
• anterior - pubic symphysis (PS)
• posterior - coccyx (C)
• lateral - ischial tuberosities (IT)
• anterolateral - ischiopubic ramus (IPR)
• posterolateral - sacrotuberous ligament
•
A line drawn between the two tuberosities separates
the diamond shaped perineum into an anterior
urogenital triangle (UG) and a posterior anal triangle

6. Boundaries of the perinium

8. Male perineum
• scrotum
• bulb of penis
• perineal body (or central tendon of the
perineum) - not as obvious as in the female
perineum and not a clinically important
structure in the male as it is in the female
• anus

9. Perineal body
• The perineal body (or central tendon of perineum)
is a pyramidal fibromuscular mass in the middle line
of the perineum at the junction between the
urogenital triangle and the anal triangle. It is found in
both males and females. In males, it is found
between the bulb of penis and the anus; in females,
is found between the vagina and anus, and about
1.25 cm in front of the latter.
• The perineal body is essential for the integrity of the
pelvic floor,

12. Female perinium
• clitoris
• labia majorum
• labia minorum
• posterior fornix
• vagina
• urethral opening
• perineal body (central tendon of the perineum)
• anus

14. anal triangle
• The anal triangle of the perineum faces
posteroinferiorly and is defined laterally by the medial
margins of the sacrotuberous ligaments, anteriorly by a
horizontal line between the two ischial tuberosities,
and posteriorly by the coccyx.
• The ceiling of the anal triangle is the pelvic diaphragm,
which is formed by the levator ani muscles.
• The anal aperture occurs centrally in the anal triangle
and is related on either side to an ischio-anal fossa. The
major muscle in the anal triangle is the external anal
sphincter.

16. Urogenital triangle
• laterally by the ischiopubic rami;
• posteriorly by an imaginary line between the
ischial tuberosities; and
• anteriorly by the inferior margin of the pubic
symphysis.

18. Pelvic Diaphragm
• The pelvic diaphragm is formed by the
important levatores ani muscles and the small
coccygeus muscles and their covering fasciae .
It is incomplete anteriorly to allow passage of
the urethra in males and the urethra and the
vagina in females