Lumbosacral Plexus Innervations

Question 1

enters thigh via obturator foramen. no pelvic structures are supplied

Obturator N. (6)

Answer 1

ADD Longus
ADD Brevis
Gracilis
Pectineus
ADD Magnus
Obturator Externus

Question 2

Femoral N. (8)

emerges btw Psoas Mjr and Iliacus. Enters thigh passing deep to inguinal

Answer 2

Sartorius
QF
RF
VM
VL
VI
Pectineus
Iliacus

Question 3

Femoral N. (2)

Skin innervation

Answer 3

Cutaneous branches: Anterior Femoral Cut (slin on anterior & lateral thigh), Saphenous . (skin on medial side of leg and foot)

Question 4

Superior Gluteal N. (3)

passes btw glute med and glut min

Answer 4

Gluteus Medius
Gluteus Minimus
TFL

Question 5

Inferior Gluteal N. (1)

enters buttock below piriformis

Answer 5

Gluteus Maximus

Question 6

Posterior Femoral Cutaneous N.

descends to posterior thigh

Answer 6

skin on buttock, thigh

Question 7

Largest nerve in body. Emerges inferior to piriformis

Sciatic N. (3)

divides at superior border of popliteal fossa into tibial and common fib

Answer 7

Hamstring Muscles (SemiT, SemiM, BF long head)

Question 8

Common Peroneal (Fibular) N.

passes behind head of fibula, winds laterally around the neck of fibula

Answer 8

Pierces Peroneus Longus where it divides into Deep Peroneal and Superficial Peroneal Nerves. Also gives rise to lateral sural cutaneous nerve

Question 9

Superficial Peroneal (Fibular) N.

Answer 9

PL, PB
at the lower 1/3 of the leg becomes cutaneous

Question 10

Superficial Peroneal (Fibular) N.

Skin innervation

Answer 10

skin on lateral lower leg and dorsum of the foot (excludes web spae btw 1st and 2nd toes)

Question 11

Deep Peroneal N.

Arises from common peroneal n.

Answer 11

anterior muscles of the leg (TA, EDL, EHL, FT)
then divides into lateral branch which innervates EHB and EDB and medial branch: skin on web space btw 1st and 2nd toes

Question 12

Tibial N.

descends vertically through popliteal fossa. Lies on popliteal muscle

passes between heads of gastroc

Answer 12

GC
Soleus
Plantaris
Popliteus
FHL
FDL
TP
at the ankle lies btw tendons of FHL and FDL, gives rise to sural cutaneous n.
terminates by dividing into medial plantar and lateral plantar n.

Question 13

Medial Plantar N.

Answer 13

ABD H
FDB
FHB
1st Lumbrical
skin of the medial 3 1/2 toes

Question 14

Lateral Plantar N.

Answer 14

QP
AbdDM
FDMB
Plantar Interossei
Lateral 3 Lumbricals
AddHal
skin: supplies skin on sole, lateral to a line splitting 4th digit

Question 15

Saphenous N.

originates from femoral n. descends with great Saphenous vein

Answer 15

supplies skin on medial side of ankle and foot

Question 16

Sural N.

Answer 16

usually arises from BOTH tibial and common fibular nerves
descends with small Saphenous vein and passes inferior to lateral malleolus to lateral side of the foot
supplies skin on posterior and lateral leg and lateral foot

Question 17

Sural N.

Answer 17

usually arises from BOTH tibial and common fibular nerves
descends with small Saphenous vein and passes inferior to lateral malleolus to lateral side of the foot
supplies skin on posterior and lateral leg and lateral foot