Sacral Plexus

Question 1

Origin of sacral plexus?

Answer 1

Anterior primary rami of L4–S4

Question 2

The sacral nerves emerge through the ____

Answer 2

Anterior sacral foramina

Question 3

Sacral nerves are joined by ___, where?

Answer 3

Lumbosacral trunk (L4–L5), anterior to piriformis

Question 4

Sacral plexus lies on the ____, anterior to ____ and covered by ____

Answer 4

Posterior pelvic wall, piriformis, and covered by piriformis muscle

Question 5

Roots of superior gluteal nerve?

Answer 5

L4, L5, S1

Question 6

Superior gluteal nerve passes through _____, runs between ____ and ____ in the gluteal region and terminates in ____

Answer 6

Greater sciatic foramen above piriformis; gluteus medius and minimus; the substance of tensor fasciae latae

Question 7

Superior gluteal nerve supplies?

Answer 7

Gluteus medius, gluteus minimus, tensor fasciae latae

Question 8

Roots of inferior gluteal nerve?

Answer 8

L5, S1, S2

Question 9

Inferior gluteal nerve passes through ____ and penetrates ____

Answer 9

Through greater sciatic foramen below piriformis, penetrates gluteus maximus

Question 10

Inferior gluteal nerve supplies?

Answer 10

Gluteus maximus

Question 11

Roots of posterior cutaneous nerve of thigh?

Answer 11

S1, S2, S3

Question 12

Posterior cutaneous nerve of thigh passes through ____

Answer 12

Through greater sciatic foramen below piriformis

Question 13

What are supplied by posterior cutaneous nerve of thigh?

Answer 13

Skin of scrotum, buttock, posterior thigh to knee

Question 14

Roots of perforating cutaneous nerve?

Answer 14

S2, S3

Question 15

Perforating cutaneous nerve perforates ___ and supplies?

Answer 15

Perforates gluteus maximus, supplies skin of buttock

Question 16

Roots of pudendal nerve?

Answer 16

S2, S3, S4

Question 17

Course of pudendal nerve?

Answer 17

Exits pelvis via greater sciatic foramen below piriformis, crosses ischial spine, re-enters perineum via lesser sciatic foramen, runs in pudendal (Alcock’s) canal with internal pudendal artery

Question 18

Branches of pudendal nerve?

Answer 18

Inferior rectal nerve, perineal nerve, dorsal nerve of penis/clitoris

Question 19

Dorsal nerve of penis/clitoris passes ____ to urogenital diaphragm while perineal nerve passes ____ to it

Answer 19

Deep; superficial

Question 20

Roots of sciatic nerve?

Answer 20

L4–S3

Question 21

Course of sciatic nerve?

Answer 21

Through greater sciatic foramen below piriformis, under gluteus maximus

Question 22

Sciatic nerves passes over which muscles?

Answer 22

Superior & inferior gemellus, quadratus femoris; adductor magnus

Question 23

Terminal branches of sciatic nerve?

Answer 23

Tibial nerve, common peroneal nerve

Question 24

Muscular branches of sciatic nerve?

Answer 24

Hamstrings and ischial part of adductor magnus

Question 25

Nerve to obturator internus roots?

Answer 25

L5, S1, S2

Question 26

Course of nerve to obturator internus?

Answer 26

Through greater sciatic foramen below piriformis, hooks around ischial spine, re-enters via lesser sciatic foramen

Question 27

Function of nerve to obturator internus?

Answer 27

Supplies obturator internus & superior gemellus

Question 28

Nerve to quadratus femoris roots?

Answer 28

L4, L5, S1

Question 29

Course of nerve to quadratus femoris?

Answer 29

Through greater sciatic foramen below piriformis, deep to sciatic nerve

Question 30

Function of nerve to quadratus femoris?

Answer 30

Supplies quadratus femoris, inferior gemellus, articular branch to hip joint

Question 31

Which three structures leave and re-enter the pelvis via lesser sciatic foramen?

Answer 31

Pudendal nerve, internal pudendal vessels, nerve to obturator internus

Question 32

Tibial nerve roots?

Answer 32

L4–S3

Question 33

Course of tibial nerve?

Answer 33

Traverses popliteal fossa, crosses popliteal vessels lateral→medial

Question 34

Tibial nerve leaves popliteal fossa then ___

Answer 34

Under soleus arch; descends with posterior tibial artery; behind medial malleolus; under flexor retinaculum

Question 35

In popliteal fossa tibial nerve crosses ___

Answer 35

Popliteal vessels lateral→medial; posterior tibial artery medial→lateral mid‑calf

Question 36

Tibial nerve terminal branches?

Answer 36

Medial plantar nerve, lateral plantar nerve

Question 37

Medial plantar nerve runs with ____ between ___ and ____

Answer 37

Medial plantar artery between abductor hallucis and flexor digitorum brevis

Question 38

Medial plantar nerve roots & supply?

Answer 38

L4, L5; medial 3½ toes, medial sole muscles

Question 39

Lateral plantar nerve roots & supply?

Answer 39

S1, S2; lateral 1½ toes, lateral sole muscles

Question 40

Common peroneal nerve roots?

Answer 40

L4–S2

Question 41

Course of common peroneal nerve?

Answer 41

Along medial biceps tendon, winds around fibular neck, divides within peroneus longus

Question 42

Branches of common peroneal nerve?

Answer 42

Genicular, lateral cutaneous nerve of calf, sural communicating, superficial peroneal, deep peroneal

Question 43

Superficial peroneal nerve roots & supply?

Answer 43

L5, S1, S2; lateral leg muscles, skin lateral leg & dorsum of foot except 1st web

Question 44

Deep peroneal nerve roots & supply?

Answer 44

L4, L5, S1, S2; anterior leg muscles, 1st web space

Question 45

Pudendal nerve passes through greater sciatic foramen between ____ and _____

Answer 45

Piriformis and coccygeus

Question 46

Branches of pudendal nerve in perineum?

Answer 46

Inferior rectal, perineal (deep & superficial), dorsal nerve of penis/clitoris

Question 47

Inferior rectal nerve innervates ___ and _____

Answer 47

External anal sphincter, perianal skin

Question 48

Inferior rectal nerve communicates with ___

Answer 48

Perineal branch of posterior femoral cutaneous nerve in ischiorectal fossa

Question 49

Perineal nerve is a branch of ____ arising _____

Answer 49

Pudendal nerve; within pudendal canal

Question 50

Branches of perineal nerve and supply?

Answer 50

Deep: perineal muscles; Superficial: posterior scrotal/labial

Question 51

Dorsal nerve of penis/clitoris runs between ___ and deep to ___

Answer 51

Between suspensory ligament layers; deep to deep fascia

Question 52

Dorsal nerve of penis/clitoris supplies?

Answer 52

Skin, prepuce, glans

Question 53

Pudendal nerve block technique?

Answer 53

Needle inserted near ischial spine via vaginal wall or through buttock

Question 54

Clinical relevance of pudendal nerve block?

Answer 54

Anesthesia of perineum for childbirth or surgery