Nerves of the Foot - Foot & Ankle

Branches of the Tibial nerve

Medial calcaneal nerve
- innervates
  - plantar medial heel
Medial plantar nerve
- innervates
  - Abductor Hallucis
  - FHB
  - FDB
  - lumbircals to 2nd and 3rd toes
- at risk
  - proper branch of medial plantar nerve at risk with medial-plantar approach to the tibial sesamoid
Lateral plantar nerve
- innervates (everything else)
  - adductor hallucis
  - quadratus plantae
  - all interossei muscles
  - lateral two lumbricals
  - abductor digiti minimus (via Baxter's nerve - the first branch of LPN)
    - Baxter`s nerve
      - courses anterior to the medial tubersosity between the QP and FDB
- provides sensation to
  - plantar lateral foot
  - lateral fourth toe
  - fifth toe
Physical exam
- injury to lateral/medial plantar nerve leads to weak or absent MTP flexion (intrinsic minus)

Sural Nerve

Provides dorsal sensory in 4th web space (70-80% of time)
Most vulnerable during
- extensile lateral approach to calcaneus
- screw placement for stress fx of proximal 5th MT
- Achilles tendon repair - especially percutaneous technique

Deep peroneal Nerve

Innervates EDB, and EHB in foot
Provides sensation to the first dorsal webspace
Found compressed beneath inferior retinaculum in anterior tarsal tunnel syndrome
Lateral branch
- most vulnerable during removal of calcaneonavicular bar
- during approach for reduction of Lisfranc injury
Injury
- injury leads to weak or absent EDB and EHB function
  - this can be seen with trauma or CMT

Superficial Peroneal Nerve

Medial branch
- dorsomedial aspect of hallux
  - most vulnerable during bunion surgery
Lateral cutaneous branch
- emerges from deep fascia 12-15 cm proximal to tip of lateral malleolus
- most vulnerable with
  - arthroscopic anterolateral portal
  - ORIF of distal fibula fx (especially Weber C)
At risk with ankle inversion injuries

Saphenous Nerve