Describe the Sciatic nerve and its nerve root
- Major nerve of the lower limb. It is a thick flat band, approximately 2cm wide – the largest nerve in the body
- Formed from ventral rami of L4-S3
Describe the root of the Sciatic nerve
- Leaves pelvis through the greater sciatic foramen
- Enters the thigh halfway between the ischial tuberosity and greater trochanter
- Passes down back thigh deep to biceps femoris, 2/3 of way down where it divides into common peroneal and tibial nerve branches
What does the sciatic nerve supply?
Articular branches to:
-Hip
Muscular branches to:
- Semitendinosis
- Semimembranosis
- Biceps femoris
- Adductor magnus (ischial head)
Describe the root of the Tibial nerve (medial branch of sciatic nerve)
- Passes through the popliteal fossa lateral, then medial, to popliteal vessels
- Enters leg under tendinous arch of soleus
- Goes most of the way down the lower leg. Lies on tibialis posterior lying between flexor digitorum longus and flexor hallucis longus
- Passes behind medial malleolus deep to flexor retinaculum
- Enters plantar aspect of foot and divides into medial and lateral plantar nerves
What does the Tibial nerve supply?
Articular branches to:
-Knee
Muscular branches to:
- Gastrocnemius
- Soleus
- Plantaris
- Popliteus
- Tibialis posterior
- Flexor digitorum and hallucis longus
What does the Medial Plantar Nerve supply?
Is one of the terminal branches of the tibial nerve
Articular branches to:
-Tarsal and Tarso-metatarsal joints
Muscular branches to:
- Abductor hallucis
- Flexor hallucis brevis
- First lumbrical
What does the Lateral Plantar Nerve supply?
Is one of the terminal branches of the tibial nerve
Articular branches to:
-Tarsal and Tarso-metatarsal joints
Muscular branches to:
- Flexor accessorius
- Flexor digiti minimi brevis
- Abductor digiti minimi
- Abductor hallucis
- Lateral 3 lumbricals
- All interossei
Describe the root of the Common Peroneal nerve (lateral branch of sciatic nerve)
- Passes along upper lateral side of popliteal fossa medial to biceps femoris
- Then passes deep to biceps femoris to arrive at posterior aspect of head of fibula
- Winds forward around neck of fibula deep to peroneus longus
- Divides into deep and superficial branches
What does the Common Peroneal Nerve supply?
Articular branches to:
- Knee
- Superior tibiofibula joint
Cutaneous branches to:
via lateral cutaneous nerve of calf
-anterior, posterior & lateral side of proximal 2/3 of leg
Describe the root of the Superficial Peroneal nerve and what it supplies
- Descends vertically between Peronei and Extensor Digitorum Longus
- In distal 1/3 of leg it divides into medial and lateral branches
- These pass over anterolateral aspect of ankle to enter foot and are entirely cutaneous
Supplies:
Muscular branches to:
-Peroneus longus and brevis
Cutaneous branches to:
-Anterolateral aspect of leg around lateral malleolus
Describe the root of the Deep Peroneal nerve
- Passes into anterior compartment of leg deep to Extensor Digitorum longus, descends on anterior surface of the Interosseous Membrane
- Passes deep to Extensor Hallucis longus and Superior Extensor retinaculae
- Enters dorsum of foot between extensor hallucis and digitorum longus and divides into medial and lateral branches
What does the Deep Peroneal Nerve supply?
Muscular branches to:
- Extensor hallucis and digitorum longus
- Tibialis anterior
- Peroneus tertius
Articular branches to:
- Inferior tibiofibular joint
- Ankle
Describe the Medial Branch of the Deep Peroneal Nerve
- Cutaneous branch
- Supplies adjacent sides of big and second toe as far as distal interphalangeal joint
Describe the Lateral Branch of the Deep Peroneal Nerve
Muscular branch to:
-Extensor digitorum brevis
Articular branch to:
-Small joints on lateral side of foot
Describe the root of the Femoral nerve
- Formed from L2-L4
- Emerges from lateral border of Psoas Major to run in a groove between Psoas Major and Iliacus
- Passes into thigh below Inguinal Ligament and enters into the femoral triangle where it lies lateral to femoral artery (NAVY)
- Here it divides into Anterior and Posterior divisions
What does the Anterior Division of the Femoral nerve supply?
Muscular branches to:
-Sartorius
Cutaneous branches
Via the medial branch of the anterior cutaneous nerve of the thigh:
-Anterior & posterior parts supplies skin over the lower part of the medial side of thigh, knee and upper leg
Via the lateral branch of the anterior cutaneous nerve of the thigh:
-Skin over anterior aspect of thigh as far down as the knee joint
What does the Posterior Division of the Femoral nerve supply?
Muscular branches to:
- Rectus femoris
- Vastus lateralis, medialis and intermedius
Articular branches to:
- Hip
- Knee
