Flexor
hallucis
brevisPlantar surfaces of
cuboid and lateral
cuneiformDivides in two, to each side of
base of proximal phalanx of
first toeThird Layer Medial plantar
nerve (S1-S2)Flexes proximal phalanx of
first toeAdductor
hallucisOblique head: bases
of second through
fourth metatarsals
Transverse head:
Ligaments of
metatarsophalangeal
jointsLateral side, base of proximal
phalanx of first toe (both heads)Third Layer Deep branch of
lateral plantar
nerve (S2-S3)Adducts first toe, maintains
transverse archFlexor digiti
minimi
brevisBase of fifth
metatarsalBase of proximal phalanx of
fifth toeThird Layer Superficial
branch, lateral
plantar nerve
(S2-S3)Flexes proximal phalanx of
fifth toePlantar
interossei
(3)Bases and medial
sides of third through
fifth metatarsalsMedial sides of bases of
proximal phalanges of third
through fifth toesFourth Layer Lateral plantar
nerve (S2-S3)Adduct second through fourth
toes and flex MP jointDorsal
interossei
(4)Adjacent sides of first
through fifth
metatarsalsFirst: medial side of proximal
phalanx of second toe
Second through fourth: lateral
sides of second through fourth
toesFourth Layer Lateral plantar
nerve (S2-S3)Abduct second through fourth
toes and flex MP jointsDorsal Muscles of Foot
Form bulge on dorsolateral surface of foot, anterior to lateral malleolus
Two muscles blend together
Extensor digitorum brevis
Proximal attachment: superior surface, anterolateral calcaneus
Splits into four muscles, each with a tendon that blends with that of long extensor
One tendon to great toe
Other tendons to second to fourth toes
Extensor hallucis brevis
Largest and most medial belly of extensor digitorum brevis
Inserts on proximal phalanx of great toe
Supplied by deep fibular nerve
Assist extensor digitorum longus in extending toesFascia
Deep fascia on dorsum of foot
Thin on dorsum
Continuous with inferior extensor retinaculum
Over lateral and posterior aspects it is continuous with plantar fascia
Deep fascia of plantar surface of foot
Central condensation of plantar fascia forms plantar aponeurosis
Arises from calcaneus
Divides into five fibrous bands that split to enclose digital tendons
Vertical septa from deep surface divide the foot into medial, central, and lateral compartments
Functions of plantar fascia
Holds foot together
Protects sole of foot from injury
Supports longitudinal arches