Nerves of the Lower Limb

Question 1

Describe features of the lumbar plexus

Answer 1

Formed from roots L1-L4. Formed within psoas major and anterior to the transverse processes of lumbar vertebrate. Has major branches for lower limb; Femoral and obturator nerve

Question 2

Describe the travel of the femoral nerve, its roots and the branches.

Answer 2

It descends behind the inguinal ligament through the femoral triangle. Roots from L2-L4. It gives off muscular, anterior cutaneous femoral and saphenous branches.

Question 3

What is the sensory innervation supply by the femoral nerve

Answer 3

Hip joint, knee joint, skin on anterior surface of thigh and skin on medial leg and foot (by saphenous vein).

Question 4

Describe the motor innervation of the femoral nerve

Answer 4

Illiacus and muscles within the anterior compartment of the thigh (Quadricepts femoris, sartorius and pectineus)

Question 5

Describe features of the saphenous nerve

Answer 5

• Terminal cutaneous branch
• Enters adductor canal with femoral vessels.
• Pierces the medial wall of adductor canal and becomes superficial
• Accompanies great saphenous vein in leg

Question 6

What is the sensory supple of the saphenous nerve and its roots

Answer 6

Roots = L3-L4.
Supplies = Skin on medial surface of knee and anteromedial surface of leg and medial malleolus

Question 7

Describe the sensory innervation of the obturator nerve and its roots

Answer 7

Roots = L2-4.
Inntervation;
- Hip joint, knee joint and upper half of medial thigh

Question 8

Describe the motor innervation of the obturator nerve

Answer 8

Obturator externus and muscles in the medial compartment of the thigh (adductor magnus, adductor longus, adductor brevis and gracilis)

Question 9

Describe features of the sacral plexus

Answer 9

Has roots L4-S4. Located on surface of posterior pelvic wall, deep to piriformis muscle

Question 10

Name the two gluteal nerves

Answer 10

Superior gluteal nerve and the inferior gluteal nerve

Question 11

Describe the features of the superior gluteal nerve

Answer 11

• Roots are L4-S1, exits pelvis through suprapiriform space, runs laterally between gluteal medius and minimus, supplies gluteus medius, gluteal minimus and tensor fasciae latae

Question 12

Describe the features of the inferior gluteal nerve

Answer 12

• Roots L5-S2, exits pelvis through infrapiriform space and innervates gluteal maximus

Question 13

Describe features of the sciatic nerve

Answer 13

Enters the gluteal region through the infrapiriform space. It descends deep to gluteus maximus, midway between the ischial tuberosity and the greater trochanter behind the hip joint.

Question 14

Where should intragluteal injections be preformed and why?

Answer 14

In the superiolateral quadrant of the buttock as this is away from the majority of the neuromuscular structures

Question 15

What is the sensory and motor innervation of the sciatic nerve

Answer 15

Sensory - Hip joint.

Motor - Muscles in the posterior compartment of thigh (hamstrings) and adductor magnus (in addition to obturator nerve)

Question 16

What are the nerves in each compartment of the leg (remember leg is not thigh!)

Answer 16

Lateral compartment - Superficial fibular nerve
Anterior compartment - Deep fibular nerve
Posterior compartment - Tibial nerve

Question 17

Describe features of the tibial nerve

Answer 17

Descends into popliteal fossa. Gives off medial cutaneous sural branch. Passes into sole behind medial malleolus and deep to flexor retinaculum. Divides into medial and lateral plantar nerves

Question 18

What is the sensory function of the tibial nerve?

Answer 18

Ankle joint and skin of the heal

Question 19

What is the motor function of the tibial nerve

Answer 19

Hamstrings (except short head biceps femoris), plantaris, popliteis, Muscles in superficial posterior compartment leg (gastrocnemius and soleus) and muscles in posterior deep compartment (Tibialis posterior, flexor hallucis longus and flexor digitorum longus)

Question 20

Describe features of the medial plantar nerve (sensory and motor supply)

Answer 20

It supplies abductor hallucis, flexor hallucis brevis, flexor digitorum brevis and lumbrical 1.
Gives sensory supply to anterior 2/3rds of sole and medial 3.5 toes

Question 21

Describe features of the lateral plantar nerve (sensory and motor supply)

Answer 21

Supplies all other plantar muscles and gives sensory supply to skin on lateral side of the anterior 2/3rds of sole and lateral 1.5 digits

Question 22

What are the other nerves in the foot (plantar side)

Answer 22

Plantar digital nerves

Question 23

Describe some features of the common fibular (peroneal) nerve

Answer 23

• It descends laterally in the popliteal fossa and gives off lateral sural cutaneous branch. It winds around the neck of the fibula and divides into superficial and deep peroneal nerves. Supplies short head of biceps femoris

Question 24

Describe features of the sural nerve

Answer 24

It is formed by the lateral cutaneous sural branch from the common fibular nerve and the medial cutaneous sural branch from the tibial nerve. It can be used as a nerve graft. It supplies the skin on the lower posterolateral surface of the leg and lateral side of the foot.

Question 25

What is the sensory innervation of the deep fibular nerve and what are its root

Answer 25

Roots = L4-5.

Ankle join and wed space between the 1st and 2nd toes

Question 26

What is the motor innervation of the deep fibular nerve

Answer 26

Muscles in the anterior compartment of the leg (tibialis anterior, extensor hallucis longus, extensor digitorum longus and fibularis tertius) Extensor digitorum brevis and extensor hallucis brevis

Question 27

What is the sensory innervation from the superficial fibular nerve and what are its roots

Answer 27

Roots = L5-S2

Sensory innervation - Ankle joint, skin on anterior distal leg, skin on dorsum of foot.

Question 28

What is the motor innervation of the superficial fibular nerve

Answer 28

Muscles in the lateral compartment of the thigh (fibularis longus and fibularis brevis)