Lecture 17, Muscles of Posterior Abdominal Wall & Pelvic Floor Muscles

Question 1

Psoas major

Answer 1

a long, thick, fusiform muscle located in the lumbar region of the trunk lateral to the lumbar vertebrae and medial to the quadratus lumborum muscle (passes inferolaterally)
function - acting inferiorly with iliacus, flexes thigh; acting superirorly, flexes vertebral column laterally to balance the trunk; when sitting, acts inferiorly with iliacus to flex trunk

Question 2

Psoas minor

Answer 2

thin, tiny muscle that starts at T12 and is placed infront of psoas major

Question 3

Iliacus

Answer 3

lying along the lateral side of the inferior part of the psoas major; together, the psoas and iliacus form the iliopsoas
function - flexes thigh and stablizes hip joint; acts with psoas major

Question 4

Quadratus lumborum

Answer 4

lies adjacent to the transverse processes of the lumbar vertebrae and lateral to the superior parts of the psoas major
function - extends and laterally flexes vertebral column; fixes 12th rib during inspiration

Question 5

Pelvic Floor

Answer 5

The pelvic floor is formed by the bowl-or-funnel shaped pelvic diaphragm, which consists of the levator ani and coccygeus muscles and the fascia covering the superior and inferior aspects of the muscles
(muscles: levator ani, coccygeus, obturator internus and piriformis)

Question 6

Coccygeus

Answer 6

forms small part of the pelvic diaphragm that supports pelvic viscera; flexes coccyx (branches of S4 & S5 nerves)

Question 7

Puborectalis (PR)

Answer 7

consists of the thicker, narrower, medial part of the levator ani, which is continous between the posterior aspects of the right and left pubic bones

Question 7

Pubococcygeus (PC)

Answer 7

the wider but thinner intermediate part of the levator ani

Question 7

Puboprostaticus (PP) (male) & Provaginalis (PV) (female)

Answer 7

Another group of muscle fibers passes around the inferior part of the prostate (in males) or posterior wall of the vagina (in females).

Question 7

Iliococcygeus

Answer 7

the posterolateral part of the tendinous arch and ischial spine; it is thin and often poorly developed and blends with the anococcygeal body posteriorly

Question 8

Obturator internus

Answer 8

laterally rotates hip joint, assists in holding head of femur in acetabulum (nerve to obturator internus (L5, S1, S2))

Question 9

Piriformis

Answer 9

laterally rotates hip joint, abducts hip joint; assists holding head of femur in acetabulum (anterior rami of S1 & S2)

Question 10

Levator ani (pubococcygeus and iliococcygeus)

Answer 10

helps support pelvic viscera; resists increases in intrabdominal pressure