Pelvic Cavity and Sacrum

Question 1

functions of the pelvic cavity

Answer 1

support urinary bladder, rectum, anal canal, reproductive tracts
contain reproductive tract in women and part of male reproductive tract

Question 2

What happens when structures in the pelvic cavity expand?

Answer 2

The pelvic cavity is continuous with the abdominal cavity so they expand upwards into there

Question 3

What is contained in the female pelvic cavity?

Answer 3

uterus, uterine tubes, vagina, bladder, terminal ureters, internal/external iliac, rectum, anal canal, anal sphincter
urethra, ovaries

Question 4

What is contained in the male pelvic cavity?

Answer 4

ductus deferens, seminal vesicles, prostate, ejaculatory duct, rectum, anal canal, anal aperture, bladder, urethra

Question 5

sacrum base vs apex

Answer 5

base is the widest part at the top, apex is the pointy end at the bottom

Question 6

What part of the sacrum does the cauda equina pass through?

Answer 6

sacral canal

Question 7

Does the coccyx have a vertebral arch?

Answer 7

No, cauda equina/nerves do not pass through the coccyx so no arch

Question 8

What is the lumbosacral joint?

Answer 8

L5 and S1, consisting of 2 facet joints and an intervertebral disc

Question 9

What ligaments stabilize the lumbosacral joint?

Answer 9

iliolumbar ligament, lumbosacral ligament, secondarily anterior longitudinal ligament
all function to reduce movement at this joint

Question 10

Why does the lumbosacral joint need to be stable?

Answer 10

It accepts weight/force transmission from the LE into the spine

Question 11

sacro iliac joint function

Answer 11

transmit force from lower limbs to vertebral column

Question 12

what ligaments stabilize sacroiliac joints

Answer 12

anterior sacroiliac ligament (thickening of joint capsule), interosseous sacroiliac ligament (largest, strongest), posterior sacroiliac ligament (covers interosseous)

Question 13

ligaments stabilizing pubic symphysis? Function?

Answer 13

superior pubic ligament, inferior pubic ligament
above and below symphysis
don’t function normally but serve as a back up to keep pubic bones together if symphysis starts to fail like in child birth

Question 14

obturator internus

Answer 14

origin: anterolateral wall of true pelvis
insertion: medial surface greater trochanter femur
innervation: nerve to obturator internus
action: ER of extended hip, abduct flexed hip

Question 15

piriformis

Answer 15

origin: anterior sacrum, btwn anterior sacral foramina
insertion: greater troch
innervation: L5-S2
action: ER extended hip, abduct flexed hip

Question 16

what forms sacral plexus?

Answer 16

L4-L5 contributions, S1-C0
dorsal and ventral

Question 17

Where do sacral plexus nerves exit?

Answer 17

out of anterior sacral foramina

Question 18

sciatic nerve

Answer 18

L4-S3
Tibial
motor: all posterior thigh except short biceps, all posterior leg, all sole of foot muscles
sensory: posterolateral/medial skin of foot/sole
Common fibular
motor: short biceps, anterior and lateral leg, ext digitorum brevis, 1st dorsal interossei
sensory: anterolateral leg skin, dorsal foot skin

Question 19

pudendal nerve

Answer 19

S2-S4
motor: skeletal m. perineum, urethral and anal sphincters, levator ani
sensory: perineum, penis, clitoris

Question 20

superior gluteal nerve

Answer 20

L4-S1
motor: glut min, med, TFL

Question 21

inferior gluteal

Answer 21

L5-S2
motor: glut max

Question 22

nerve to obturator internus and superior gemellus

roots

Answer 22

L5-S2
motor: obturator internus and superior gemellus

Question 23

nerve to quadratus femoris and inferior gemellus

Answer 23

L4-S1
motor: quadratus femoris and inferior gemellus

Question 24

posterior femoral cutaneous nerve

Answer 24

S1, S3
sensory: posterior thigh skin

Question 25

nerve to piriformis

Answer 25

S2-3
sensory: gluteal fold skin
motor: piriformis

Question 26

nerves to levator ani, coccygeous, external anal sphincter

Answer 26

S4
motor: evator ani, coccygeous, external anal sphincter
sensory: skin btwn anus and coccyx

Question 27

coccygeal plexus formed by

Answer 27

S4 small contribution, mainly formed by anterior rami of S5 and C0

Question 28

anococcygeal nerves

Answer 28

S4-C0
senosry: perianal skin