Anatomy of the Lower Body

• tibialis anterior

• extensor digitorum longus

• fibularis tertius

• extensor longus hallucis

muscles in the anterior compartment of the leg

proximal 2/3 of the anteriorlateral tibia

tibialis anterior origin

medial + inferior surfaces of medial cuneiform and base of 1st metatarsal

tibialis anterior insertion

anterior fibula and interosseous membrane

extensor digitorum longus origin

middle and distal phalanges of lateral four digits

extensor digitorum longus insertion

distal 1/3 of anterior fibula and interosseous membrane

fibularis tertius origin

base of 5th metatarsal

fibularis tertius insertion

anterior fibula and interosseous membrane

extensor hallucis longus origin

dorsal aspect of base of distal phalanx of great toe

extensor hallucis longus insertion

L4-L5

nerve roots for tibialis anterior innervation

deep fibular nerve

nerve that innervates tibialis anterior

L5-S1

nerve roots for extensor digitorum longus

deep fibular nerve

nerve that innervates extensor digitorum longus

L5-S1

nerve roots for extensor hallucis longus innervation

deep fibular nerve

nerve that innervated extensor hallucis longus

L5-S1

nerve roots for fibularis tertius

deep fibular nerve

nerve that innervates fibularis tertius

dorsiflexion of ankle joint and foot inversion

main action of tibialis anterior

extends digits 2-5, ankle dorsiflexion

extensor digitorum longus main action

ankle joint dorsiflexion, foot eversion

fibularis tertius main action

great toe extension, ankle dorsiflexion

extensor hallucis longus main action

fibularis longus, fibularis brevis

muscles of the lateral compartment of the leg

head of the fibula and lateral fibula

fibularis longus origin

base of 1st metatarsal and medial cuneiform

fibularis longus insertion

distal 1/3 of lateral fibula

fibularis brevis origin

dorsal surface of lateral tuberosity on 5th metatarsal

fibularis brevis insertion

foot eversion, weak ankle plantar flexion, resist foot inversion

fibularis longus main action

foot eversion, weak ankle plantar flexion, resist foot inversion

fibularis brevis main action

superficial fibular nerve

nerve that innervates fibularis longus

L5, S1, S2

nerve branches for fibularis longus innervation

superficial fibular nerve

nerve that innervates fibularis brevis

L5, S1, S2

nerve branches for fibularis brevis

anterior tibial artery

artery that supplies blood flow for the anterior compartment of the leg

fibular (peroneal) artery

artery that supplies blood flow for the lateral compartment of the leg

anterior tibial veins

veins of the anterior compartment of the leg

proximally to the dorsal aspect of the ankle joint

superior extensor retinaculum location

anterior aspect of lateral distal fibula

superior extensor retinaculum lateral attachment

anterior aspect of medial distal tibia

superior extensor retinaculum medial attachment

house muscles of anterior compartment of the leg

superior extensor retinaculum function

lateral aspect of calcaneus around peroneal trochlea

inferior peroneal retinaculum insertion

Posterior border and tip of the lateral malleolus

superior peroneal retinaculum origin

lateral aspect of the calcaneus and deep fascia of the leg

superior peroneal retinaculum insertion

Secures fibular tendons as they split and travel toward their attachment points.

inferior peroneal retinaculum function

primary anchor for fibular tendons

superficial peroneal retinaculum function

extensor hallucis brevis, extensor digitorum brevis

muscles of the dorsum of the foot

calcaneus, floor of tarsal sinus

extensor digitorum brevis origin

base of proximal phalanx of toes 2-4

extensor digitorum brevis insertion

calcaneus, first of the tarsal sinus

extensor hallucis brevis origin

proximal phalanx of great toe

extensor hallucis brevis insertion

extends digits 2-4

extensor digitorum brevis action

extends great toe

extensor hallucis brevis action

deep fibular nerve

nerve that innervates extensor digitorum brevis

L5, S1

nerve roots for extensor digitorum brevis

deep fibular nerve

nerve that innervates extensor hallucis brevis

L5-S1

nerve roots for extensor hallucis brevis

dorsalis pedis

artery that supplies blood to the dorsum of the foot

• anterior inferior tibiofibular ligament (AITFL)

• posterior inferior tibiofibular ligament (PITFL)

• transverse tibiofibular ligament (TTFL)

• interosseous tibiofibular ligament (IOL)

ligaments in the distal tibiofibular joint

fibrous (syndesmosis)

distal tibiofibular joint type

deep fibular nerve

cutaneous innervation of the yellow section

saphenous nerve

cutaneous innervation of the medial posterior foot (green) section

superficial fibular nerve

cutaneous innervation of the midfoot (orange) section

dorsal lateral cutaneous nerve

cutaneous innervation of the lateral foot (blue section)

• flexor digitorum brevis

• abductor hallucis

• abductor digiti minimi

muscles in the first layer of the plantar foot

calcaneal tuberosity and plantar aponeurosis

flexor digitorum brevis origin

middle phalanges of toes 2-5

flexor digitorum brevis insertion

flexes toes 2-5

flexor digitorum brevis action

medial plantar nerve

nerve that innervates flexor digitorum brevis

L5, S1

nerve branches for flexor digitorum brevis

medial process of tuberosity of calcaneus, flexor retinaculum, and plantar aponeurosis

abductor hallucis origin

medial side of base of proximal phalanx of big toe

abductor hallucis insertion

abducts and flexes big toe

abductor hallucis action

medial plantar nerve

nerve that innervates abductor hallucis

L5, S1

nerve branches for abductor hallucis

medial and lateral processes of tuberosity of calcaneus, plantar aponeurosis, and intermuscular septa

abductor digiti minimi origin

lateral side of base of proximal phalanx of 5th digit

abductor digiti minimi insertion

abducts and flexes 5th digit

abductor digiti minimi action

lateral plantar nerve

nerve that innervates abductor digiti minimi

S1-S3

nerve roots for abductor digiti minimi

• quadratus plantae

• lumbricals

muscles in the 2nd layer of the plantar foot

medial surface and lateral margin of plantar surface of calcaneus

quadratus plantae origin

posterolateral margin of tendon of flexor digitorum longus

quadratus plantae insertion

flexes lateral four digits

quadratus plantae action

lateral plantar nerve

nerve that innervates quadratus plantae

S1-S3

nerve branches for quadratus plantae

tendons of flexor digitorum longus

lumbricals origin

medial aspect of extensor expansion of lateral four digits

lumbricals insertion

flex proximal phalanges and extends middle and distal phalanges of digits 2-5

lumbricals action

medial plantar nerve

nerve innervation for medial lumbrical

lateral plantar nerve

nerve innervation for lateral three lumbricals

L5, S1

nerve branches for medial lumbrical

S1-S3

nerve branches for lateral three lumbricals

• flexor hallucis brevis

• adductor hallucis

• flexor digiti minimi

muscles in the 3rd layer of the plantar foot

plantar surface of cuboid and lateral cuneiforms

flexor hallucis brevis origin

both sides of base of proximal phalanx of big toe

flexor hallucis brevis insertion

flexes proximal phalanx of first digit

flexor hallucis brevis action

medial plantar nerve

nerve that innervates flexor hallucis brevis

L5, S1

nerve branches for flexor hallucis brevis

bases of metatarsals 2-4

adductor hallucis oblique head origin

plantar ligaments of MTP joints

adductor hallucis transverse head origin

lateral side of base of proximal phalanx of big toe

adductor hallucis insertion (for both heads)