peripheral nerves of lower limb anatomy.pptx

peripheral nerves

1. Peripheral nerves of lower limb Bhagyalakshmi M 18-02-2025 1

2. Introduction Formed by lumbar plexus (L1-L4) in posterior abdominal wall and sacral plexus (L4-S4) in pelvis Main nerves of lower limb: Femoral nerve Obturator nerve Sciatic nerve Tibial nerve Common peroneal nerve Superficial peroneal nerve Deep peroneal nerve 18-02-2025 2

3. F emoral nerve Anetrior compartment of thigh Motor branch: iliacus and all muscles of anterior compartment Cutaneous: anterior and medial aspect of the thigh, medial side of leg, and foot. 18-02-2025 3

4. Injury Due to pelvic fracture or direct trauma Motor loss-: weak thigh flexion due to paralysis of iliacus and sartorius inability to extend knee due to quariceps femoris paralysis Sensory loss: Sensory loss over medial side of leg and foot upto ball of great toe ( first MTP joint) due to saphenous nerve injury 18-02-2025 4

5. Obturator nerve Nerve of adductor compartment of thigh Sensory : lower half of medial aspect of thigh. Injury : Anterior dislocation of knee joint 18-02-2025 5

6. Sciatic nerve Nerve of anterior compartment of thigh Motor: muscles of back of thigh- extend hip and flex knee Tibial nerve – flexion of leg and foot muscles and plantar flexion Common peroneal - dorsiflexion 18-02-2025 6

7. Sensory : 1) Tibial nerve- back of calf, medial and lateral sides of heel, lateral border of foot and sole 2) Common peroneal nerve- anterolateral and lateral surface of leg and dorsum of foot except site by deep peroneal nerve 18-02-2025 7

8. Injury Due to posterior dislocation of hip, pelvic fracture, mis displaced gluteal region injection ( most common cause) Motor loss: – Inability to extend the thigh and flex the knee, due to paralysis of the hamstring muscles. – Loss of all movements below the knee with foot drop, due to paralysis of all the muscles of the leg and foot. The motor loss leads to flail foot which leads to great difficulty in walking. The patient walks with high stepping gait. 18-02-2025 8

9. Tibial nerve Motor braches - posterior compartment of leg and sole Sensory – medial and lateral plantar nerves supply whole sole of foot Injury – Due to posterior dislocation of knee joint or lacerated wound in popliteal fossa 1) Sensory loss: The loss of sensation in the sole and plantar aspects of the toes including the dorsal aspects of their distal phalanges, due to involvement of the cutaneous branches 18-02-2025 9

10. Injury Motor loss: – Foot is held dorsiflexed and everted, due to paralysis of the muscles of posterior compartment of the leg. – Loss of prominence of calf and tendocalcaneus , due to paralysis of the triceps surae muscle (gastrocnemius and soleus ). – Loss of plantar flexion of foot, due to paralysis of the flexors of ankle. – Inability to stand on the toes, due to loss of plantarflexion of foot. 18-02-2025 10

11. Common peroneal nerve Winds around posterolateral neck of fibula Injury – Foot drop, due to the paralysis of muscles of the anterior compartment of the leg (dorsiflexors of the foot). Loss of extension of toes, due to the paralysis of extensor digitorum longus and extensor hallucis longus. Loss of eversion of foot, due to the paralysis of peroneus longus and peroneus brevis (evertors of the foot) The sensory loss due to involvement of the cutaneous branches, on the anterolateral aspect of the leg, and whole of dorsum foot except the areas supplied by the saphenous and sural nerves. 18-02-2025 11

12. Deep peroneal nerve motor branches - all the muscles of the anterior compartment of the leg sensory branches- the skin of cleft between the great and second toes. 18-02-2025 12

13. Superficial peroneal nerve Motor branch – lateral compartment of leg muscles Sensory branch – dorsum of foot except first cleft space. 18-02-2025 13