MSK - Cutaneous Innervation of the Lower Limb Flashcards
Define cutaneous innervation
“an area of skin supplied by a specific nerve
Where do cutaneous branches arise from and where do they travel?
Arise from mixed nerves and travel into the subcutaneous tissue
Where do the majority of the mixed nerves arise from in the lower limb?
Lumbar and Sacral plexuses
Where are the two places that the cutaneous nerves can arise from?
1 - Directly from the lumbar or sacral plexuses
2 - As cutaneous branches of the mixed nerves that arise from the lumbar or sacral plexusus
Where is the lumbar plexus located?
What roots does it consist of?
Anterior to the transverse processes of the lumbar spine
L1 to L4 (with some contribution from T12)
Generally, where do the nerves arising from the lumbar plexuses supply?
Anterior and Medial thigh
What are some major nerves that arise from the lumbar plexus?
**Obturator Nerve **(L2-L4)
**Femoral Nerve **(L2-L4)
What spinal roots make up the Sacral Plexus?
L5-S4
What areas does the sacral plexus supply?
What is its main branch?
Posterior thigh, leg and foot
Sciatic Nerve
What are the three major nerves of the lower limb?
Femoral Nerve
Tibial Nerve
Common Fibular Nerve
What cutaneous innervation of the lower limb in the femoral nerve responsible for?
Anteriomedial thigh
Medial Leg and Foot
What is a mixed nerve?
Which major leg nerve is a mixed nerve?
Contained sensory and motor functions
Femoral Nerve
What plexus does the femoral nerve arise from?
Describe the course of the femoral nerve
The lumbar plexus
Descends through the psoas major muscle and enters the lower limb on the anterior aspect of the thigh
What two cutaneous nerves arise from the femoral nerve?
Anterior cutaneous branches
Saphenous Nerve
Where does the saphenous nerve arise?
Describe the course of the saphenous nerve
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
Where does the saphenous nerve supply?
Skin on the medial side of the leg and foot
Where do the anterior cutaneous branches arise from?
Where do these nerves innervate?
Arise in the femoral triangle
Innervate the skin of the aterior and medial aspects of the thigh
What cutaneous innervation is the tibial nerve responsible for?
Posterolateral leg
Sole
Heel
The tibial nerve is one of the terminal branches of what?
The sciatic nerve
Where does the tibial nerve arise?
Describe the course of the tibial nerve
Apex of the popliteal fossa
Descends down the posterior compartment of the leg
Name the cutaneous branches of the tibial nerve
Sural Nerve
Medial Plantar Nerve
Lateral Plantar Nerve
Calcaneal Nerves
What is the sural nerve formed by?
Where does it supply?
Branches of the tibial and common fibular nerves
Supplies the skin of the posterolateral leg and the lateral margin of the foot
Where does the medial plantar nerve supply?
Skin of the medial sole of the foot, and the plantar aspect, nails and sides of the medial three and a half toes
Where does the Lateral Plantar Nerve supply?
Skin of the lateral sole, and the plantar aspect, nails and sides of the lateral one and a half toes
Where does the Calcaneal nerve supply?
Skin of the heel
Label cutaneous innervation to the posterior leg
Label the cutaneous innervation to the sole of the foot
What cutaneous innervation is the common fibular nerve responsible for?
Anterolateral leg, posterolateral leg and the dorsal surface of the foot
Where does the common fibular nerve arise?
Where does it enter?
Apex of the popliteal fossa
Enters the lateral compartment
What are the cutaneous branches of the common fibular nerve?
Superficial fibular nerve (Mixed)
Deep fibular nerve (Mixed)
Sural nerve
Lateral Sural Nerve
Describe the course of the Superficial fibular nerve
Where does it innervate?
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)
Where does the deep fibular nerve supply?
Supplies the web of skin between the big and 2nd toes
What is the Sural nerve comprised of?
Where does it innervate?
Formed by branches of the tibial and common fibular nerves
Supplies the skin of the posterolateral leg and the lateral margin of the foot
Where does the lateral sural nerve supply?
Supplies part of the anterolateral leg
Label the sensory innervation of the legs and feet
