Anatomy of the Perineum

Perineum
Borders and Ceiling
The perineum is inferior to the
pelvic floor

Anterior point = inferior border
of pubic symphysis

Posterior point = tip of coccyx

Lateral points = ischial
tuberosity

Peripheral boundary = pelvic
outlet

Ceiling = pelvic diaphragm

Lateral walls = pelvic cavity
walls

The perineum is divided into:

Anterior urogenital triangle

Contain openings of urinary
systems + reproductive
systems

Posterior anal triangle

Contain anus + external
anal sphincter

Perineal Membrane + Deep Perineal Pouch:

Urogenital diaphragm = skeletal
muscle sphincter in male

This muscle is enclosed in
superior + inferior fascia




Perineum 1

, Perineal membrane =
inferior fascia

Urethra sphincters are is also
enclosed in the perineal membrane
+ superior fascia

⇒ deep perineal pouch is the area
between superior + inferior fascia

⇒ Both provide support for the external
genitalia




Anal Triangle
External anal sphincter is a major muscle in the anal triangle

It surrounds the anal canal

In the anal canal

Submucosal venous plexus are plenty → many longitudinal veins (3 main
veins)

These veins create folds of the mucosa, called columns of Morgagni

These columns join at the anal valves

There are glands that open into each of the column



Urogenital Triangle
Superficial Perineal Pouch
The superficial perineal pouch is between the perineal membrane and
membranous layer of superficial fascia

Erectile Tissues:

Two sets of erectile structures join to form penis + clitoris

Corpora cavernosa, on each side of the urogenital triangle, with the
proximal end anchored to the pubic arch




Perineum 2