1. Perineum General features
Region of below pelvic diaphragm(the levator ani and coccygeus muscles)
anus

2. Boundaries
A diamond-shape space whose boundaries are those of the pelvic outlet
Lower border of symphysis pubis
Rami of pubis and ischium
Ischial tuberosities
Sacrotuberous ligament
The coccyx

3. Two triangles
An imaginary line drawn between the two ischial tuberosities divides perineum into anterior and posterior triangles
Urogenital triangle (anterior)－differs in male and female
Anal triangle (posterior)－similar in both sexes

4. Urogenital triangle
contains the roots of the external genital organ and the openings of the urogenital system.
ischiopubic rami
ischial tuberosity
levator ani muscle

5. Anal triangle ischial tuberosity sacrotuberous ligament anus
tip of the coccyx

6. Highlight
Position and divisions of perineum.