Foot Anatomy

Foot Anatomy

Superficial – plantar aponeurosis with lateral cord (what rips off the base of 5th metatarsal)

Layer 1: Abductor hallucis
Flexor digitorum brevis (big thick muscle, just under plantar aponeurosis)
Abductor digiti minimi

Layer 2: Quadratus plantae
Flexor digitorum longus tendons
Flexor hallucis longus tendon
Lumbricals (with flexor digitorum longus)

Layer 3: Adductor hallucis – oblique and transverse bands
Flexor hallucis brevis (with two heads going into the sesamoids)
Flexor digiti minimi brevis

Layer 4: Interossei – 4 dorsal, 3 plantar
Peroneus longus
Long plantar ligament

Note that the medial and lateral plantar nerves are protected from puncture by the thick plantar aponeurosis and the thick first layer (consisting of FDB, AbdH, AbdDM)

Lateral Plantar Nerve
– smaller than medial
– innervates abductor digiti minimi and quadratus plantae, flexor digit minimi, and sometimes the plantar and dorsal interossei of the 4th interosseous space
– the deep branch then innervates the adductor hallucis, the lateral 3 lumbricals, and the remaining interosseous spaces

Medial Plantar Nerve
– the larger of the two plantar nerves
– innervates the abductor hallucis, flexor hallucis brevis, flexor digitorum brevis, and the most medial lumbrical