MSK - Cutaneous Innervation of the Lower Limb

Question 1

Define cutaneous innervation

Answer 1

“an area of skin supplied by a specific nerve

Question 2

Where do cutaneous branches arise from and where do they travel?

Answer 2

Arise from mixed nerves and travel into the subcutaneous tissue

Question 3

Where do the majority of the mixed nerves arise from in the lower limb?

Answer 3

Lumbar and Sacral plexuses

Question 4

Where are the two places that the cutaneous nerves can arise from?

Answer 4

1 - Directly from the lumbar or sacral plexuses

2 - As cutaneous branches of the mixed nerves that arise from the lumbar or sacral plexusus

Question 5

Where is the lumbar plexus located?

What roots does it consist of?

Answer 5

Anterior to the transverse processes of the lumbar spine

L1 to L4 (with some contribution from T12)

Question 6

Generally, where do the nerves arising from the lumbar plexuses supply?

Answer 6

Anterior and Medial thigh

Question 7

What are some major nerves that arise from the lumbar plexus?

Answer 7

**Obturator Nerve **(L2-L4)

**Femoral Nerve **(L2-L4)

Question 8

What spinal roots make up the Sacral Plexus?

Answer 8

L5-S4

Question 9

What areas does the sacral plexus supply?

What is its main branch?

Answer 9

Posterior thigh, leg and foot

Sciatic Nerve

Question 10

What are the three major nerves of the lower limb?

Answer 10

Femoral Nerve

Tibial Nerve

Common Fibular Nerve

Question 11

What cutaneous innervation of the lower limb in the femoral nerve responsible for?

Answer 11

Anteriomedial thigh

Medial Leg and Foot

Question 12

What is a mixed nerve?

Which major leg nerve is a mixed nerve?

Answer 12

Contained sensory and motor functions

Femoral Nerve

Question 13

What plexus does the femoral nerve arise from?

Describe the course of the femoral nerve

Answer 13

The lumbar plexus

Descends through the psoas major muscle and enters the lower limb on the anterior aspect of the thigh

Question 14

What two cutaneous nerves arise from the femoral nerve?

Answer 14

Anterior cutaneous branches

Saphenous Nerve

Question 15

Where does the saphenous nerve arise?

Describe the course of the saphenous nerve

Answer 15

Arises in the femoral triangle

Descends down the thigh, via the adductor canal, exits the canal just before the adductor hiatus, crossing the medial aspect of the knee and passing deep to the sartorius tendon

Question 16

Where does the saphenous nerve supply?

Answer 16

Skin on the medial side of the leg and foot

Question 17

Where do the anterior cutaneous branches arise from?

Where do these nerves innervate?

Answer 17

Arise in the femoral triangle

Innervate the skin of the aterior and medial aspects of the thigh

Question 18

What cutaneous innervation is the tibial nerve responsible for?

Answer 18

Posterolateral leg

Sole

Heel

Question 19

The tibial nerve is one of the terminal branches of what?

Answer 19

The sciatic nerve

Question 20

Where does the tibial nerve arise?

Describe the course of the tibial nerve

Answer 20

Apex of the popliteal fossa

Descends down the posterior compartment of the leg

Question 21

Name the cutaneous branches of the tibial nerve

Answer 21

Sural Nerve

Medial Plantar Nerve

Lateral Plantar Nerve

Calcaneal Nerves

Question 22

What is the sural nerve formed by?

Where does it supply?

Answer 22

Branches of the tibial and common fibular nerves

Supplies the skin of the posterolateral leg and the lateral margin of the foot

Question 23

Where does the medial plantar nerve supply?

Answer 23

Skin of the medial sole of the foot, and the plantar aspect, nails and sides of the medial three and a half toes

Question 24

Where does the Lateral Plantar Nerve supply?

Answer 24

Skin of the lateral sole, and the plantar aspect, nails and sides of the lateral one and a half toes

Question 25

Where does the Calcaneal nerve supply?

Answer 25

Skin of the heel

Question 26

Label cutaneous innervation to the posterior leg

Answer 26

Question 27

Label the cutaneous innervation to the sole of the foot

Answer 27

Question 28

What cutaneous innervation is the common fibular nerve responsible for?

Answer 28

Anterolateral leg, posterolateral leg and the dorsal surface of the foot

Question 29

Where does the common fibular nerve arise? Where does it enter?

Answer 29

Apex of the popliteal fossa Enters the lateral compartment

Question 30

What are the cutaneous branches of the common fibular nerve?

Answer 30

**Superficial fibular nerve** (Mixed) **Deep fibular nerve** (Mixed) **Sural nerve** **Lateral Sural Nerve**

Question 31

Describe the course of the Superficial fibular nerve Where does it innervate?

Answer 31

Moves through the lateral compartment of the leg and perforates the deep fascia of the leg Innervates the skin of the anterolateral leg and dorsum of the foot (apart from the skin between the big and 2nd toes)

Question 32

Where does the deep fibular nerve supply?

Answer 32

Supplies the web of skin between the big and 2nd toes

Question 33

What is the Sural nerve comprised of? Where does it innervate?

Answer 33

Formed by branches of the tibial and common fibular nerves Supplies the skin of the posterolateral leg and the lateral margin of the foot

Question 34

Where does the lateral sural nerve supply?

Answer 34

Supplies part of the anterolateral leg

Question 35

Label the sensory innervation of the legs and feet

Answer 35