The Muscles of the Foot

The Muscles of the Foot

THE MUSCLES OF THE FOOT

LEARNING OBJECTIVES

At the end of the lecture, the student should be able to:

  • Describe the dorsal muscles of foot.
  • Tell the origin and insertion of planter muscles of foot.
  • Explain their nerve supply and actions.

THE DORSAL MUSCLES OF THE FOOT

EXTENSOR DIGITORUM BREVIS:

ORIGIN:

1. Forepart of the upper and lateral surfaces of the

calcaneum.

2. From the inferior extensor retinaculum.

Passes obliquely across the dorsum of the foot, and ends in four tendons.

INSERTION:

1. Medial, the largest, is inserted into the dorsal surface of the base of the proximal phalynx of the great toe—the Extensor hallucis brevis.

2. Other three inserted into the lateral sides of the tendons of the Extensor digitorum longus of the second, third, and fourth toes.

NERVE SUPPLY:

Deep peroneal nerve.

FUNCTION:

Extends the phalanges of the four toes.

THE PLANTAR MUSCLES OF THE FOOT:

The muscles of the sole of foot are conveniently described in four layers from the inferior layer superiorly.

A) THE FIRST LAYER

•Abductor hallucis.

•Flexor digitorum brevis.

•Abductor digiti minimi.

B) THE SECOND LAYER

•Quadratus plantae

•Lumbricals.

•Flexor Digitorum Longus Tendon.

•Flexor Hallucis longus Tendon.

C)THE THIRD LAYER

•Flexor hallucis brevis.

•Adductor hallucis.

•Flexor digiti minimi brevis.

D)THE FOURTH LAYER:

•Dorsal interossei

•Plantar interossei

•Peroneus longus tendon.

•Tibialis posterior tendon.

THE FIRST LAYER

ABDUCTOR HALLUCIS:

Medial border of the foot.

ORIGIN:

•Medial process of the tuberosity of the Calcaneus.

•Flexor Retinaculum.

INSERTION:

•Tibial side of the base of the proximal phalanx of the great toe.

NERVE SUPPLY:

Medial Planter nerve.

ACTION: Flexes and abducts big toe; braces medial longitudinal arch

FLEXOR DIGITORUM BREVIS:

Middle ofthe Sole Of The Foot

ORIGIN:

•Medial process of the tuberosity of the Calcaneus.

INSERTION:

  • Four tendons to four lateral toes -
  • Sides of the middle phalanx about its middle, tendons perforated by those of the flexor digitorum longus.

NERVE SUPPLY:Medial planter nerve.

ACTION: Flexes lateral four toes; braces medial and longitudinal lateral arches

ABDUCTOR MINIMI DIGITI:

LATERAL BORDER OF THE FOOT:

ORIGIN:

•Lateral process of the tuberosity of the Calcaneus,

•The forepart of the medial process of calcaneum.

INSERTION:

•Into the fibular side of the base of the proximal phalanx of the fifth toe.

NERVE SUPPLY:Lateral Planter Nerve.

ACTION: Flexes and abducts big toe; braces lateral longitudinal arch.

Quadratus PlantaeB) THE SECOND LAYER

•Quadratus plantae

•Lumbricals.

•Flexor Digitorum Longus Tendon.

•Flexor Hallucis longus Tendon.

QUADRATUS PLANTAE / FLEXOR DIGITORUM ACCESSORIUS

•ORIGIN :arises by two heads:

•Medial or larger head _muscular is attached to the medial concave surface of the Calcaneus.

•Lateral head, flat and tendinous, arises from the lateral border of the inferior surface of the Calcaneus,

•End in a flattened band.

INSERTION:

•Lateral margin and upper and under surfaces of the tendon of the Flexor digitorum longus.

NERVE SUPPLY: Lateral plantar nerve.

ACTION:

Assists flexor digitorum longus in flexing lateral four toes.

LUMBRICALS:

ORIGIN:

•Foursmall muscles.

•Arise from tendons of the Flexor digitorum longus.

INSERTION:

•Expansions of the tendons of the Extensor digitorum longus on the dorsal surfaces of the proximal phalanges of lateral four toes.

NERVE SPPLY:

First lumbrical: Medial Plantar Nerve

Remainder: Lateral Plantar nerve

ACTION: Extends toes at Interphalangeal joint.

Flexor Hallucis Brevis

C)THE THIRD LAYER

•Flexor hallucis brevis.

•Adductor hallucis.

•Flexor digiti minimi brevis.

FLEXOR HALLUCIS BREVIS

ORIGIN:

•Cuboid bone

•The contiguous portion of the third cuneiform

•From the prolongation of the tendon of the Tibialis posterior

INSERTION:

•Into the medial and lateral sides of the base of the proximal phalanx of the great toe.

NERVE SUPPLY:

Medial plantar nerve.

ACTION: Flexes Metatarsophalangeal joint of big toe; supports medial longitudinal arch.

ADDUCTOR HALLUCIS:

ORIGIN:

•Arises by two heads—oblique and transverse

OBLIQUE HEAD:

ORIGIN:

Arise by bases of the second, third, and fourth metatarsal bones

INSERTED:

Lateral side of the base of the proximal phalanx of the great toe

TRANSVERSE HEAD:

•Arises from the plantar metatarsophalangeal ligaments of the third, fourth, and fifth toes and

INSERTION :

•lateral side of the base of the proximal phalanx of the great toe

NERVE SUPPLY

Deep branch lateral planter nerve

ACTION:

Flexes Metatarsophalangeal joint of big toe; holds together metatarsal bones.

Flexor Hallucis BrevisFLEXOR DIGITI MINIMI BREVIS

ORIGIN:

•Base of the fifth metatarsal bone,

•INSERTION:

•Lateral side of the base of the proximal phalanx of the fifth toe

NERVE SUPPLY:

Lateral plantar nerve.

ACTION:

Flexes metatarsophalangeal joint of little toe.

D)THE FOURTH LAYER:

•Dorsal interossei

•Plantar interossei

•Peroneus longus tendon.

•Tibialis posterior tendon.

PLANTAR INTEROSSEI:

•Three in number.

ORIGIN:

•The bases and medial sides of the bodies of the third, fourth, and fifth metatarsal bones

INSERTION:

•medial sides of the bases of the proximal phalanges of the lateral three toes

NERVE SUPPLY:

Lateral Planter nerve

ACTION:

Adduction of toes,

Flexesmetatarsophalangeal joints and extends Interphalangeal joint.

DORSAL INTEROSSEI:

•Four in number.

ORIGIN:

• By Twoheads from the adjacent sides of the metatarsal bones

INSERTION:

•The bases of the proximal phalanges.

•The aponeurosis of the tendons of the extensor digitorum longus.

NERVE SUPPLY:

Lateral plantar nerve.

ACTION:

Adduction of toes; flexes Metatarsophalangeal joints and extends interphalaneal joints

Learning Resources

•Text from:

– Grays Anatomy.

–Clinical Anatomy by Regions. Richard S. Snell.

•Images from:

–.

–antar_nerve.

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