Sacral Plexus Part 1

Question 1

What anterior primary rami form the sacral plexus?

Answer 1

L4, L5, S1-S3 and part of S4

Question 2

Which rami contribute to the sacral plexus by way of the lumbosacral trunk?

Answer 2

L4 and L5

Question 3

What muscle does the sacral plexus form on the anterior surface of?

Answer 3

piriformis

Question 4

When do the nerve roots that form the sacral plexus divide into anterior and posterior divisions?

Answer 4

shortly after exiting their IVF/sacral foramen

Question 5

What roots contribute fibers to the nerve to the quadratus femoris and gemellus inferior?

Answer 5

L4, L5, and S1 nerves

Question 6

Virtually every major nerve of the sacral plexus leaves the pelvic cavity via what opening?

Answer 6

greater sciatic foramen

Question 7

T/F: the nerve to the quadratus femoris and gemellus inferior leaves the pelvis thru the greater sciatic foramen to supply muscles which contribute to lateral rotation and abduction of the thigh.

Answer 7

False; should say aDDuction

Question 8

What nerve exits the pelvis thru the greater sciatic foramen, re-enters via the lesser sciatic foramen and supplies muscles that contribute to lateral rotation and abduction of the thigh?

Answer 8

nerve to the obturator internus and gemellus superior

Question 9

What roots contribute to the nerve to the obturator internus and gemellus superior?

Answer 9

L5, S1, and S2

Question 10

T/F: the nerve to the obturator internus and gemellus superior re-enters the pelvis via the lesser sciatic foramen to supply the gemellus superior.

Answer 10

False; re-enters to supply obturator internus– nerve to obturator internus and gemellus superior gives off branches to gemellus superior after exiting greater sciatic foramen before re-entering pelvis

Question 11

What roots contribute to the pudendal nerve?

Answer 11

S2, S3, and S4

Question 12

which nerve leaves the pelvis via the greater sciatic foramen, arches around the ischial spine and into the perineum via the lesser sciatic nerve?

Answer 12

pudendal nerve

Question 13

What structure does the pudendal nerve travel through inferior to the pubic symphysis to reach the dorsal side of the penis/clitoris?

Answer 13

pudendal canal

Question 14

What are the 3 major branches that come off of the pudendal nerve inside the pudendal canal?

Answer 14

inferior rectal nerves, perineal nerve, and the terminal branch of the pudendal nerve (dorsal nerve of the penis/clitoris)

Question 15

Which branch of the pudendal nerve carries sensory info from the skin around the anus and inferior 2/3 of the anal canal?

Answer 15

inferior rectal nerves

Question 16

What nerve is the motor supply to the external anal sphincter?

Answer 16

inferior rectal nerve of the pudendal nerve

Question 17

After the perineal nerve is given off of the pudendal nerve in the pudendal canal, what does it divide into?

Answer 17

deep and superficial branches

Question 18

What muscles are supplied by the deep branches of the perineal nerve?

Answer 18

external anal sphincter, bulbospongiosus, ischiocavernosus, and superficial transverse perineus

Question 19

What kind of info is carried by the superficial branches of the perineal nerve?

Answer 19

sensory

Question 20

What area is supplied by the superficial branches of the perineal nerve in males? in females?

Answer 20

posterior scrotum, urethral mucosa, and bulb of penis;

labium majus, external urethral orifice, and vestibule

Question 21

what muscles are supplied by the terminal branch of the pudendal nerve?

Answer 21

deep transverse perineus and urethral sphincter muscles

Question 22

What is the name given to the terminal branch of the pudendal nerve?

Answer 22

dorsal nerve of the penis/clitoris

Question 23

What areas does the terminal branch of the pudendal nerve carry sensory info from?

Answer 23

in males: corpus cavernosum, glans penis, and skin covering penis;
in females: corpus cavernosum and clitoris

Question 24

Individual muscular branches off the sacral plexus supply the levator ani and coccygeus muscles. Where do these fibers originate?

Answer 24

S4

Question 25

What roots contribute to the pelvic splanchnic nerves?

Answer 25

S2, S3, and S4