Pelvic Wall

Question 1

What are the functions of the pelvis?

Answer 1

1) Attachment for lower limb muscles
2) protect pelvic viscera
3) support abdominopelvic viscera
4) attachment of erectile bodies and external genitalia on perineal membrane
5) attachment of muscles on pelvic floor
6) bear weight

Question 2

What makes up the boney pelvis?

Answer 2

The pelvic = ilium, ischium, and pubic; sacrum; coccyx.

Question 3

What is the thickest portion of the ilium and what is its significance?

Answer 3

The arcuate line bears the weight dispersing function of the pelvis.

Question 4

What runs through the anterior and posterior formina of the sacrum? Be specific.

Answer 4

The rami of spinal nerves. Ventral rami leave anterior foramina. Dorsal rami leave posterior famina.

Question 5

Which ligament divides the lesser and greater sciatic notches into lesser and greater sciatic foramina?

Answer 5

The sacrospinous ligament.

Question 6

Which ligament helps to close off the lesser sciatic notch to complete the lesser sciatic foramen?

Answer 6

The sacrotuberous ligament.

Question 7

What is the pelvic inlet or superior pelvic aperture?

Answer 7

It is an area of the pelvis from the promontory of sacrum to ala of sacrum to arcuate line to pectineal line (pecten pubis) to pubic creast to pubic symphysis. It also divides the pelvis into 2 regions, the greater and lesser, or false and true, pelvis.

Question 8

What is the linea terminalis?

Answer 8

The combined structure made of the arcuate lines, pectineal lines, pubic crests

Question 9

Where is the greater (false) pelvis?

Answer 9

Superior to pelvic inlet and contains ala of ilium and iliac crest - and abdominal muscles

Question 10

Which part of the pelvis is inferior to the pelvic inlet and contains visceral structures?

Answer 10

The lesser (true) pelvis.

Question 11

What is the pelvic outlet?

Answer 11

Area of the pelvis including pubic arch, ischiopubic rami, ischial tuberosities, tip of coccyx, sacrotuberous ligaments

Question 12

What is superficial and inferior to the pelvic outlet?

Answer 12

The perineum.

Question 13

Which gender has a rounder pelvic inlet and a subpubic angle of 90 degrees?

Answer 13

Female.

Question 14

Which gender has a heart-shaped pelvic inlet and a subpubic angle of 50-60 degrees?

Answer 14

Male.

Question 15

What is the interspinous distance?

Answer 15

The variable, most narrow part of the pelvic canal between the ischial spines.

Question 16

What are the 3 categories of conjugates that describe the anterior-posterior distance of the pelvic inlet?

Answer 16

1) True conjugate - distance between superior aspect of pubic symphysis and sacral promontory
2) Obstetrical conjugate - distance between thickest/middle part of pubic symphysis and sacral promontory
3) Diagonal conjugate - distance between inferior aspect of pubic symphysis and sacral promontory.

Question 17

Why would the interspinous distance increase? How much can it increase?

Answer 17

Pregnancy/delivery; 10-15% with hormones

Question 18

What are the muscles of the pelvic wall?

Answer 18

1) Obturator internus

2) Piriformis

Question 19

Obturator internus

Answer 19

Obturator forament; greater trochanter of femur
Inn: nerve to obturator internus
F: lateral rotation of hip and abduction of hip

Question 20

Piriformis

Answer 20

Anterior surface of sacrum; grater trochanter
Inn: nerve to piriformis
F: later rotation of hip and abduction of hip

Question 21

What are the muscles of the pelvic diaphragm?

Answer 21

1,2) Levator ani = pubococcygeus + iliococcygeus

3) Coccygeus or ischococcygeus

Question 22

Pubococcygeus

Answer 22

Pubis bone to coccyx’ supports pelvic viscera, attaches to perineal body, medial part forms puborectalis muscle

Question 23

Iliococcygeus

Answer 23

tendinous arch off inferior boarder of obturator internus tendon to ischial spine; support viscera

Question 24

Coccygeus or Ischococcygeus

Answer 24

Attaches superior to ischial spine and anterior surface of sacrum

Question 25

Which nerve innervates the muscles of the pelvic diaphragm?

Answer 25

The pudendal nerve.