Sacral Plexus Part 2 (Posterior division)

Question 1

What nerve supplies the piriformis muscle and which roots contribute fibers?

Answer 1

nerve to the piriformis; fibers from S1 and S2

Question 2

What roots contribute fibers to the superior gluteal nerve?

Answer 2

L4, L5, and S1

Question 3

After the superior gluteal nerve exits the pelvis via the greater sciatic foramen, what does it split into?

Answer 3

superior and inferior branches

Question 4

What muscle does the superior gluteal nerve exit the pelivs superior to?

Answer 4

piriformis

Question 5

T/F: the inferior branches of the superior gluteal nerve supply the gluteus maximus.

Answer 5

False; inferior branches of superior gluteal nerve supply the gluteus medius, gluteus minimis and tensor fascia lata

Question 6

What muscles are supplied by the superior branches of the superior gluteal nerve?

Answer 6

gluteus medius and minimus

Question 7

What nerve leaves the pelvis via the greater sciatic foramen, inferior to the piriformis, to supply the gluteus maximus? what roots contribute fibers?

Answer 7

inferior gluteal nerve;

L5, S1, and S2

Question 8

What roots contribute to the perforating cutaneous nerve?

Answer 8

S2 and S3

Question 9

How does the perforating cutaneous nerve get its name?

Answer 9

it penetrates the sacrotuberous ligament on its way to the lower medial aspects of the buttocks

Question 10

T/F: the perforating cutaneous nerve may be formed by a branch off the pudendal nerve or be absent altogether.

Answer 10

True

Question 11

what two nerves are formed by both anterior and posterior divisions of the sacral plexus?

Answer 11

posterior cutaneous nerve of the thigh and sciatic nerve

Question 12

What roots/divisions form the posterior cutaneous nerve of the thigh?

Answer 12

anterior divisions of S2 and S3 and posterior divisions of S1 and S2

Question 13

What nerve leaves the pelvis via the greater sciatic foramen, descends thru the posterior thigh and inferior to the leg where it ultimately communicates with the sural nerve?

Answer 13

posterior cutaneous nerve of the thigh

Question 14

What skin is supplied by the posterior cutaneous nerve of the thigh?

Answer 14

skin of the posterior and medial thigh

Question 15

What is the largest nerve in the human body?

Answer 15

sciatic nerve

Question 16

The sciatic nerve is commonly about 2 cm in diameter and formed by two nerves. What are the two nerves that combine to form the sciatic nerve?

Answer 16

tibial and common fibular nerves

Question 17

The tibial nerve is more medial than the common fibular nerve. Where do the fibers of the tibial nerve come from?

Answer 17

the anterior divisions of the L4-S3 nerves

Question 18

Where do the fibers of the common fibular nerve come from?

Answer 18

The posterior divisions of the L4-S2

Question 19

T/F: the sciatic nerve leaves the pelvis via the greater sciatic foramen, below the piriformis, with both parts in individual sheaths.

Answer 19

False; both parts are in a common sheath

Question 20

What muscle does the sciatic nerve travel on the posterior aspect of in the thigh?

Answer 20

adductor magnus

Question 21

Where does the sciatic nerve split into its tibial and common fibular components?

Answer 21

about 2/3 of the way to the knee (lower 3rd of the thigh)

Question 22

T/F: the point at which the sciatic nerve may be further or the two parts may be separate all the way.

Answer 22

True

Question 23

What muscle does the common fibular nerve give off branches to in the thigh before separating from tibial nerve fibers?

Answer 23

biceps femoris (short head)

Question 24

After separating from the tibial nerve, the common fibular nerve follows its course around the fibula where it gives off an articular branch. What joint does the common fibular nerve send an articular branch to upon reaching the antero-lateral aspect of the leg?

Answer 24

knee joint

Question 25

Where are the two sensory branches given off of the common fibular nerve? What are they named?

Answer 25

given off as the nerve courses around the lateral aspect of the politeal fossa;
lateral sural cutaneous nerve and fibular communicating branch

Question 26

What supplies the skin on the lateral aspect of the leg?

Answer 26

lateral sural cutaneous nerve

Question 27

What nerve forms the sural nerve after combining with the medial sural cutaneous nerve?

Answer 27

fibular communicating branch

Question 28

After giving off the two sensory branches what does the common fibular nerve divide into?

Answer 28

superficial fibular nerve and the deep fibular nerve

Question 29

What two structures does the superficial fibular nerve travel between on it way to the dorsum of the foot?

Answer 29

fibularis longus and the fibula

Question 30

What does the superficial fibular nerve split into in order to supply the skin over the dorsum of the foot?

Answer 30

medial dorsal cutaneous nerve and the intermediate dorsal cutaneous nerve

Question 31

What muscles are supplied by the superficial fibular nerve?

Answer 31

fibularis longus and fibularis brevis

Question 32

T/F: the superficial fibular nerve is completely cutaneous.

Answer 32

False

Question 33

What part of the dorsum of the foot is not supplied by the branches of the superficial fibular nerve?

Answer 33

the skin between the first 2 toes

Question 34

T/F: the deep fibular nerve is primarily sensory in nature.

Answer 34

False; primarily muscular

Question 35

What muscle does the deep fibular nerve run along on its way to the dorsum of the foot?

Answer 35

tibialis anterior

Question 36

What 6 muscles are supplied by the deep fibular nerve?

Answer 36

extensor muscles of the foot and toes (tibialis anterior, extensor digitorum longus, extensor digitorum brevis, extensor hallucis longus, extensor hallucis brevis, and fibularis tertius)

Question 37

What is supplied by the terminal branch of the deep fibular nerve?

Answer 37

skin between the first two toes (sensory)

Question 38

What clinical consideration is associated with the deep fibular nerve, results in weak dorsiflexion, and is aka “foot slap.”

Answer 38

steppage gait

Question 39

T/F: patients with steppage gait commonly have an orthotic device.

Answer 39

True

Question 40

T/F: patients with steppage gait may also have weak everters.

Answer 40

True