peroneal nerve Flashcards
Explain the origin, root value, course, distribution, and termination of the common peroneal nerve.
Root ⇒ Dorsal rami of L4, L5, S1, S2
O ⇒ Smaller terminal division of the sciatic nerve arises at the distal third of the thigh, near the apex of the popliteal fossa
Course in the back of thigh and entering the fossa:
1. It traverses with sciatic nerve primarily and then the popliteal fossa inferolaterally towards the fibular head.
Course in the popliteal fossa:
2. In the fossa, it is positioned medially to the tendon of the biceps femoris muscle and lateral to the gastrocnimeus muscle
3. It follows the tendon to the back of the head of the fibula.
Course as it leaves the popliteal fossa
4. Then it leaves the fossa and turns around the lateral aspect of the neck of fibula
T ⇒ Divides into two terminal branches, the superificial and deep fibular (peroneal) nerves, underneath the peroneus longus muscle.
Distribution:
1. Articular branches to the knee joint
2. Sensory branches of the lateral sural cutaneous nerve (sensation inferolaterally to the knee) and the medial sural cutaneous nerve (from tibial nerve) to form the sural nerve which innervates the skin of the lateral foot and lateral lower ankle
explain the applied anatomy associated with the common peroneal nerve.
Applied Anatomy:
1. Common peroneal nerve is the most frequently injured nerve in the lower limb (fractured neck of fibula).
2. May get entrapped between the attachments of peroneus longus to the head and shaft of fibula
3. Patients present with foot drop due to weaknes sof dorsiflexion.
Explain the origin, root value, course, distribution, and termination of the superficial peroneal nerve.
Root ⇒ Ventral primary rami of L5 and S1
O ⇒ SMaller terminal branch of the common peroneal nerve. It begins on the lateral side of the neck of fibula under cover of upper fibres of peroneus longus.
Course in upper 1/3 of leg:
1. Descends through the substance of the peroneous longus
Course in the middle 1/3 of leg:
2. Descends for a short distance b/w the pernoeus longus and brevis muscles
3. Reaches the atnerior border of peroneus brevis
4. Descends in a groove b/w the peroneus brevis and the extensor digitorum longus under cover of deep fascia
Course at the junction of upper 2/3 and lower 1/3:
5. It pierces the deep fascia to become superfiial
T ⇒ Medial branch and lateral branch at the distal part of the leg.
- Medial branch ⇒ divides into 2 dorsal digital nerves → supplies the medial side of big toe and adjoining side sof 2 and 3 toe.
- Lateral branch ⇒ divides into 2 dorsal digital nerves → supplies the adjoining sides of 3 and 3 toe, and 4th and 5th tose.
Distribution:
Muscular branches:
- Peroneus longus and peroneus brevis (lateral leg compartment)
Cutaneous branches
- Supplies the lower 1/3 of the lateral side of the leg
- Greater part of the dorsum of foot. Except for the terriotires supplied by the saphenous, sural, deep peroneal, and plantar nerves.
Communicating branches:
- Medial branch communicates with the saphenous and deep peroneal nerves.
- Lateral branch communicates with the sural nerve.
Explain the origin, root value, course, distribution, and termination of the deep peroneal nerve
Root ⇒ ventral primary rami of L4, L5, S1, S2
O ⇒ Begins on the lateral side of the neck of fibula. It is one of the terminal branches of the common peroneal nerve
Course in the proximal 2/3 of the leg:
1. Enters the atnerior compartment by piercing the anterior intermuscular septum
2. Then pierces the extensor digitorum longus and lies lateral to the anterior tibial artery
Course in the distal 1/3 of the leg:
3. Becomes anterior to the anterior tibial artery
Course towards the dorsum of foot:
4. Then again, it lies anterior to the tibial artery just proximal to the ankle joint and together they enter the dorsum of the foot deep to the extensor retinaculum.
T ⇒ Ends on the dorsum of the foot, distal to the ankle joint. It also divides into the medial and lateral terminal branches
- Medial terminal branch ⇒ ends by supplying the skin adjoining the 1st interdigital cleft and gives articular branch to the first metatarsophalangeal joint
- Lateral terminal branch ⇒ turns laterally and supplying extensor digiorum brevis and extensor hallucis brevis muscles. The tarsal joint as well as the three matatarsophalangeal joints.
Distribution;
Muscular branches:
- Tibialis anterior, extensor digitorum longus, extensor hallucis longus, and preoneus tertius (anterior leg compartment)
- Extensor digitorum brevis and extensor hallucis brevis on the dorsum of the foot.
Cutaneous branches:
- Supplies the adjacent sides of the 1st and 2nd toes
Articular branches:
- Supplies the ankle joint, tarsal joints, tarsometatarsal and metatarsophalangeal joints.
explain the applied anatomy associated with the deep peroneal nerve
Clinical Aspects:
1. Injury to the deep peroneal nerve can cause paralysis of the muscles of the anterior compartment of the leg
2. Foot drop due to loss of dorsiflexion of foot.
3. Commonly caused by trauma, leprosy, or peripheral neuritis
4. Sensory loss is confined to the 1st interdigital cleft
explain the applied anatomy associated with the superficial peroneal nerve.
Clinical Aspects:
1. Superficial peroneal nerve can get entrapped as it penetrates the deep fascia of the leg
2. May be involved in lateral compartment syndrome
3. Paralysis causes loss of eversion of foot at subtalar joint.
