DR. SREEKANTH THOTA DEPARTMENT OF ANATOMY Lower limb Foot

The Foot The muscles in the sole of the foot are organized into four layers. Blood supply: Posterior tibial artery Nerve supply: Tibial nerve

Plantar aponeurosis Plantar aponeurosis is a thickening of deep fascia in the sole of the foot. Its apex is attached to the medial and lateral tubercles of the calcaneum. The base of the aponeurosis divides into five slips that pass into the toes.

Muscles of the Sole of the Foot First layer: 1.Abductor hallucis 2. Flexor digitorum brevis 3.Abductor digiti minimi

Abductor hallucis Origin: calcaneum Insertion: Base of proximal phalanx of big toe Nerve Supply: Medial plantar nerve Action: Abducts big toe

Flexor digitorum brevis Origin: Calcaneum Insertion: Four tendons to four lateral toes inserted into borders of middle phalanx Nerve Supply: Medial plantar nerve Action: Flexes lateral four toes

Abductor digiti minimi Origin: Calcaneum Insertion: Base of proximal phalanx of fifth toe Nerve Supply: Lateral plantar nerve Action: Abducts fifth toe

Second Layer 1. Quadratus plantae: 2. Lumbricals (4) 3. Flexor digitorum longus tendon 4. Flexor hallucis longus tendon

Quadratus plantae Origin: Calcaneum Insertion: Tendon of flexor digitorum longus Nerve Supply: Lateral plantar nerve Action: Assists flexor digitorum longus in flexing lateral four toes

Lumbricals (4) Origin: Tendons of flexor digitorum longus Insertion: Dorsal extensor expansion Nerve Supply: First lumbrical: medial plantar nerve. 2 nd,3 rd and 4th: lateral plantar nerve Action: Extends toes at interphalangeal joints

Third Layer 1. Flexor hallucis brevis 2. Adductor hallucis 3. Flexor digiti minimi brevis

Flexor hallucis brevis Origin: Cuboid, lateral cuneiform Insertion: Medial tendon into medial side of base of proximal phalanx of big toe; lateral tendon into lateral side of base of proximal phalanx of big toe Nerve Supply: Medial plantar nerve Action: Flexes metatarsophalangeal joint of big toe

Flexor digiti minimi brevis Origin: Base of fifth metatarsal bone Insertion: Lateral side of base of proximal phalanx of little toe Nerve Supply: Lateral plantar nerve Action: Flexes metatarsophalangeal joint of little toe

Adductor hallucis Origin: transverse head bases of third, fourth and fifth metatarsal bones oblique head from plantar ligaments Insertion: Lateral side of base of proximal phalanx of big toe Nerve Supply: lateral plantar nerve Action: adduct 1st digit

Fourth layer of muscles 1. Dorsal interossei : 4 (DAB) 2. Plantar interossei : 3 ( PAD)

Dorsal interossei : 4 (DAB) Origin: Adjacent sides of metatarsal bones Insertion: Bases of proximal phalanges first: medial side of second toe remainder: lateral sides of second, third, and fourth toes also dorsal extensor expansion Nerve Supply: Lateral plantar nerve Action: Abduction of toes

Plantar interossei : 3 ( PAD) Origin: Inferior surfaces of third, fourth, and fifth metatarsal bones Insertion: Medial side of bases of proximal phalanges of lateral three toes Nerve Supply: Lateral plantar nerve Action: Adduction of toes

Dorsal aspect Extensor digitorum brevis ORIGIN: Anterior part of upper surface of the calcaneum Insertion: By four tendons into the proximal phalanx of big toe and long extensor tendons to second, third, and fourth toes Nerve Supply: Deep peroneal nerve Action: Extends toes

Arteries Blood supply to the foot is by branches of the posterior tibial and dorsalis pedis (dorsal artery of the foot) arteries.

Posterior tibial artery and plantar arch 1. Lateral plantar artery 2. Medial plantar artery

Dorsalis pedis artery Branches 1. Tarsal arteries 2. Arcuate artery 3. First dorsal metatarsal artery 4. deep plantar artery: joins with plantar arch

Tibial nerve 1. LATERAL plantar nerve: Innervates all intrinsic muscles in the sole except for the muscles (abductor hallucis, flexor digitorum brevis, flexor hallucis brevis, and first lumbrical). 2. MEDIAL plantar nerve

Deep fibular nerve The deep fibular nerve innervates extensor digitorum brevis, Supplies general sensory branches to the skin on the adjacent dorsal sides of the first and second toes and to the web space between them