Atlas of Human Anatomy by Netter

GUIDE

Pelvis and Perineum: Perineum and External Genitalia: Male

[Plate 361, Male Perineum and External Genitalia (Deeper Dissection)]

Perineum

General organization (Same as female)

Narrow region between superior medial aspects of thigh

With lower limbs abducted in lithotomy position, becomes a diamond-shaped area

Bounded by pelvic diaphragm superiorly and superficial fascia and skin inferiorly

Anal canal, urethra, and vagina (females) pass through the perineum

Boundaries:

Anteriorly: Pubic symphysis

Posteriorly: Inferior sacrum and coccyx

Anterolaterally: Ischiopubic rami

Laterally: Ischial tuberosities

Posterolaterally: Sacrotuberous ligaments

Divided into two triangles by imaginary line between ischial tuberosities

Posteriorly is anal triangle

Anteriorly is urogenital triangle

Contents of anal triangle (Same as female)

Anal canal and anus

External and internal anal sphincters

Ischiorectal fossa

Contents of urogenital triangle

Membranous and spongy urethra (males); distal urethra (females)