Sacral Plexus

Question 1

What is the sacral plexus formed by

Answer 1

anterior primary rami of L4, L5, S1-3, and part of S4

Question 2

where do the contributions of L4 and L5 come from?

Answer 2

lumbosacral trunk

Question 3

the plexus forms on the anterior surface of what muscle

Answer 3

piriformis

Question 4

nerve to quadratus femoris and gemellus inferior fibers and actions

Answer 4

L4, L5, S1 lateral rotation and adduction of the thigh

Question 5

this nerve leaves the pelvis through the greater sciatic foramen before re-entering the pelvis through the lesser sciatic foramen

Answer 5

nerve to the obturator internus and gemellus superior

Question 6

nerve to the obturator internus and gemellus superior fibers and action

Answer 6

L5, S1, S2, lateral rotation and abduction

Question 7

branches off of the pudendal nerve within the pudendal canal

Answer 7

inferior rectal and perineal

Question 8

nerve that carries sensor info from the skin around the anus and inferior 2/3 of the anal canal, provides motor supply to the external anal sphincter

Answer 8

inferior rectal nerves

Question 9

deep branch of the perineal nerve supplies these muscles

Answer 9

external anal sphincter, bulbospongiosus, ischiocavernosus, superficical transverse perineus

Question 10

superifical branch of the perineal nerve carry sensory fibers from this

Answer 10

in males: posterior scrotum, urethral mucosa, and bulb of penis
In females: labium majus, external urethral orifics, and vestibule

Question 11

the terminal branch of the pudendal nerve

Answer 11

males: dorsal nerve of the penis females: clitoris

Question 12

the dorsal nerve of the penis or clitoris supply these muscles

Answer 12

deep transverse perineus, urethral sphincter

Question 13

the dorsal nerve also carries sensory information from these areas

Answer 13

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

Question 14

nerve to the piriformis fibers

Answer 14

s1 and s2

Question 15

superior gluteal nerve fibers

Answer 15

l4, l5, s1

Question 16

the superior branches of the superior gluteal nerve supply these muscles

Answer 16

gluteus medius and minimus

Question 17

the inferior branches of the superior gluteal nerve supply these muscles

Answer 17

gluteus medius, gluteus minimus, tensor fascia lata

Question 18

inferior gluteal nerve fibers

Answer 18

l5, s1, s2

Question 19

inferior gluteal nerve supplies these muscles

Answer 19

gluteus maximus

Question 20

the perforating cutaneous nerve pierces this membrane

Answer 20

sacrotuberous ligament

Question 21

the perforating cutaneous nerve fibers

Answer 21

anterior divisions s2, s3 and posterior divisions of s1 and s2

Question 22

Nerves that make up the sciatic nerve and their fibers

Answer 22

medial = tibial nerve formed from the anterior divisions of L4-S3

Lateral = common fibular nerve formed from the posterior divisions of L4-S2

Question 23

the sciatic nerve travels posterior to this muscle

Answer 23

adductor magnus

Question 24

common fibular nerve supplies this muscle in the thigh

Answer 24

biceps femoris (short head)

Question 25

sensory branches of the common fibular nerve

Answer 25

the lateral sural cutaneous nerve - supplies the skin of the lateral aspect of the leg

fibular communicating branch - forms the sural nerve after combining with the medial sural cutaneous

Question 26

the common fibular divides into a superficial fibular nerve that supplies these muscles

Answer 26

fibularis longus and fibularis brevis

Question 27

common fibular –> superficial fibular –> medial dorsal cutanous and intermediate dorsal cutaneous nerves sensory supply

Answer 27

dorsum of foot except for skin between first two toes

Question 28

common fibular nerve damage, specifically to the deep fibular nerve that supplies the extensors

Answer 28

steppage gait aka foot drop

Question 29

while combined with the common fibular nerve the tibial nerve supplies these muscles

Answer 29

biceps femoris (long head), semitendinosus, semimembranosus, adductor magnus

Question 30

in the popliteal fossa the tibial nerve gives off two branches, an articular branch supplying the knee and the muscular branches supplying these muscles

Answer 30

popliteus, gastrocnemius, soleus, and plantaris

Question 31

muscular branches of the tibial nerve supply these muscles in the leg and a medial calcaneal sensory branch

Answer 31

flexor digitorum longus, flexor hallicus longus, tibialis posterior

Question 32

after traveling around the medial malleolus to the planter surface of the foot it divides into these two termianl branches

Answer 32

medial plantar nerve, lateral plantar nerve

Question 33

medial plantar nerve muscle supply

Answer 33

abductor hallicus, flexor digitorum brevis, flexor hallicus brevis

Question 34

medial plantar nerve divisions

Answer 34

common plantar digital nerves - motor supply to lumbricals 1 and 2

proper plantar digital nerves - sensory supply to skin between the toes

Question 35

lateral plantar nerve division

Answer 35

superficial branch - skin around 5th digit

deep branch - adductor hallicus, flexor digiti minimi brevis, abductor digit minimi, quadratus plantae, lateral lumbricals interossei muscles