tibial nerve Flashcards
Explain the tibial nerve origin and root value
O ⇒Tibial Nerve begins at the upper angle of the popliteal fossa as one of the terminal branches of the sciatic nerve. Ocassionally the sciatic nerve divides high up inside the pelvis, in the gluteal region
Root ⇒ Ventral primary rami of L4, L5, S1, S2, S3.
Explain the course and termination of the Tibial N.
Course in Popliteal Fossa:
1. Enters the popliteal fossa through its upper angle while being associated ith the popliteal vessels.
2. In the upper part, it is lateral to the vessels, then crossing the vessels in the middle part. In the distal part it lies medial to the vessels. Running vertically.
Course in the posterior compartment of the leg:
3. At the lower end of the popliteal fossa, it passes between the heads of gastrocnemius and deep to the tendinous arch of the soleus.
4. At the distal margin of the popliteus muscle it continues to run in the posterior compartment of leg, along with the poserior tibial vessels, but now swaps back to thelateral side.
Course at the ankle
5. The Tibial nerve is lateral to the posterior tibial artery
6. It passes deep to the flexor retinaculum between the tendons of the flexos halucis longus and the flexor digitorum longus (also a small branch called the medial calcaneal nerve, before the flexor retinaculum)
Termination:
7. The Tibial N. terminates posteroinferior to the medial malleolus.
8. Then it divides into the medial and lateral plantar nerves deep to the flexor retinaculum
Describe the main branches of the TIbial N.
In the popliteal Fossa:
Musc. → Five muscular branches to the lateral and medial head of gastrocnemius, plantaris, soleus, and popliteus.
Cut. → Branches into the sural nerve which descends b/w heads of gastrocnemius and pierces deep fascia of leg to become superficial. Supplies posterior part of leg and lateral border of foot + lateral margin of little toe
Art.→ Superior medial, inferior medial and middle genicular nervres supply the knee joint
In the Leg:
Musc. → Tibialis posterior which innervates flexor digirtorum longus, and flexor hallucis longus. Soleus may also receive a branch in the leg.
Cut. → Medial calcanean branch, pierce the flexor retinaculum to supply the skin over heel.
Art. → Ankle joint
In the foot:
- Medial Plantar and Lateral Plantar Nerve
Describe the Origin, Course and Branches of the Medial Plantar Nerve
-Medial Plantar nerve has proper digital branch to great toe (which also has a branch to the flexor hallucis brevis more distally), the common plantar digital nerves.
The first common digital nerve has a branch to the first lumbrical. Common digital nerves (1,2,3) divide further into the proper digital branches for adjacent sides of 1st and 2nd, 2nd and 3rd, and 3rd and 4th (none for 5th).
- The Medial Plantar cutaneous areas for the medial 3.5 digits skin on sole of foot and the nail beds of those toes.
Describe the Origin, Course and branches of the Lateral Plantar Nerve
Origin:
- Branch of the tibial nerve, deep to the flexor retinaculum near the medial malleolus.
Course:
1. The lateral plantar nerve enters the sole under the cover of abductor hallucis and then passes forward and laterally across the sole in an oblique direction to reach the tuberosity of the fifth metatarsal bone
- During the oblique course of the lateral plantar nerve, it lies between the flexor accesorius muscle of the second layer, and flexor digitorum brevis muscle of the first layer
2. It then divides into the superficial and deep branches.
Termination:
3. The lateral plantar nerve terminates between the flexor digitorum brevis and abductor digiti minimi
Branches and Supply:
1. The trunk of the lateral plantar
- Supplies the flexor digitorum accessorius, and the abductor digiti minimi.
- Cutaneous branches to the skin of the lateral part of the sole
- The superificial branch of the lateral plantar nerve
- Runs distally along the lateral border of the sole and divides into two common plantar digital nerves.
- The lateral common plantar digital nerve supplies 3 muscles → the flexor digiti minimi brevis, fourth (5th toe) dorsal interosseous and 3rd (4th toe) planter interosseous muscle
- The medial common plantar digitial nerve divides into the proper plantar digital nerves for the adjacent sides of the fourth and fifth toes.
- The nerves extend onto the dorsum and supply the nail bedes and tips of the toes (4th and 5th) - The deep branch of the lateral plantar nerve
- Turns medially from the base of the 5th metatarsal bone and travels across the sole, b/w the muscles of the 3rd and 4th layers and terminates into the adductor hallucis muscle.
- Carries only motor fibers, which supply the lateral three lumbricals, 1st 2nd and 3rd dorsal interossei, 1st and 2nd plantar interossei and adductor hallucis
Describe the Applied and Clinical Aspects of the Tibial N.
Cuase of injury and symptoms:
1. Tibial nerve can be injured by deep lacerations in the popliteal fossa, or posterior dislocation of the knee joint, or severance of the tibial nerve
- Symptoms → Paralysis of the flexor muscles in the leg, intrinsic muscles in the sole of the foot.
→ No plantarflexion of ankle or toes
→ No sensation on the sole of the foot
- Medial plantar nerve compression may occur during repetitive eversion of the foot (during gymnastics and running) because of its frequency in runners
- Symptoms → joggers foot - Morton Metatarsalgia
- Communication b/w the most lateral digital branch of medial plantar nerve, adnt he medial branch of the lateral nerve. The neurofibroma arises in this communcation.
- Can be caused by pressure of a tight-fitting shoe which results in severe pain in the third and fourth toes. - Tarsal Tunnel Syndrome
- Tibial N is compressed in the osseofibrous tunnel deep to the flexor retinaculum.
- Symptoms of burning, tingling and pain in the sole of the foot.
- Surgical division of the flexor retinaculum relieves the servere and persistent pain
- Sural nerve is easily accessible and can be used for nerve grafting.
