2-6 Anatomy of the Pelvis: Boundaries and Borders

Question 1

What are the contents and placement of the false/greater pelvis?

Answer 1

1. Superior to pelvic inlet

2. Contains abdominal organs (ileum, sigmoid colon)

Question 2

What are the contents and placement of the true/lesser pelvis?

Answer 2

1. Inferior to pelvic inlet
2. Contains: rectum, bladder, reproductive organs
3. Separated from perineum by pelvic outlet (enclosed by pelvic diaphragm).

Question 3

What are the boundaries of the pelvic brim/inlet?

Answer 3

1. Bounded by:
   a. Pubic crest
   b. Pectineal line
   c. Arcuate line
   d. Promontory and ala of sacrum
   e. a+b+c = “terminal line”
2. Separates true and false pelves

Question 4

What are the boundaries of the pelvic outlet?

Answer 4

1. Bounded by:
   a. Pubic symphysis
   b. Ischiopubic ramus
   c. Ischial tuberosity
   d. Sacrotuberous ligament
   e. Coccyx
2. Separates true pelvis from perineum

Question 5

What separates lesser pelvis from perineum?

Answer 5

Pelvic diaphragm

Question 6

What partially closes the pelvis inferiorly? What passes through it?

Answer 6

1. Pelvic diaphragm
   Hammock-shaped set of muscles which partially close the pelvis inferiorly.

The pelvic diaphragm is incomplete centrally to allow for passage of viscera from pelvis to perineum; rectum and urethra and in the female, the vagina (urogenital/levator hiatus).

Question 7

What forms the lateral boundaries of the urogenital hiatus?

Answer 7

puborectalis