Foot Anatomy

Muscles of the Foot

  Muscle Innervation Origin Insertion Action Nerve Root
  Dorsal layer          
1 Extensor digitorum brevis(EDB) Deep peroneal superolateral calcaneus base of proximal phalanges extend  
  First Plantar Layer          
1 Abductor hallucis med plantar calcaneal tuberosity base of great toe prox phalanx abduct great toe  
2 Flexor digitorum brevus(FDB) med plantar calcaneal tuberosity distal phalanges of 2nd-5th toes flex toes  
3 Abductor digiti minimi lat plantar calcaneal tuberosity base fo 5th toe abduct small toe  
  Second Plantar Layer          
1 Quadratus plantae lat plantar med & lat calcaneus FDL tendon helps flex distal phalanges  
2 Lumbricals med & lat plantar FDL tendon EDL tendon flex MTP, extend IP  
3 FDL & FHL tibial tibia/fibula distal phalanges of digits flex toes/invert foot  
  Third Plantar Layer          
1 Flexor hallucis brevis(FHB) med plantar cuboid/lat cuneiform proximal phalanx of great toe flex great toe  
2 Adductor hallucis lat plantar oblique:2nd-4th metatarsals, Transverse:MTP proximal phalanx of great toe lat adduct great toe  
3 Flexor digiti minimi brevis(FDMB) lat plantar base of 5th metatarsal head proximal phalanx of small toe flex small toe  
  Forth Plantar Layer          
1 Dorsal interosseous(DIO) lat plantar metatarsal dorsal extensors abduct  
2 Plantar interosseous lat plantar 3rd-5th metatarsals proximal phalanges medially adduct toes  
3 (Peroneus longus and tibialis posterior superficial peroneal/tiba fibula/tiba med cuneiform/navicular everts/invert foot  
calcaneous superior Calcaneous Anatomy

talus posterior

talus lateral

Anterior portion of the talar dome is @2.4mm wider than the posterior portion, making the ankle much more stable in dorsiflexion than in plantarflexion.
dorsal foot sensation  
  Spring ligament (calcaneonavicular) extends from the anterior aspect of the sustentaculum tali to the plantar medial surface of the navicular.  Supports the plantar medial margin of the talar head. Two main components: superomedial calcaneonavicular ligament and inferior calcaneonavicular ligament.  Superomedial calcaneonavicular ligament  is commonly attenuated or torn in adult-acquired flatfoot deformity.