Week 14 Foot Muscles PDF

The Foot Actions of the Muscles of the Sole of the Foot  actions of muscles of sole of foot are not very important individually because fine control of individual toes is not important to most people  muscles of sole of foot function primarily as a group in posture and locomoti...

The Foot Actions of the Muscles of the Sole of the Foot  actions of muscles of sole of foot are not very important individually because fine control of individual toes is not important to most people  muscles of sole of foot function primarily as a group in posture and locomotion  also help to maintain arches of foot and resist forces that tend to flatten arches of foot Intrinsic Muscles of the Sole of the Foot  First Layer  Abductor Hallucis  most medially located in 1st layer  Origin: medial tubercle of calcaneal tuberosity  Insertion: medial side of base of proximal phalanx of great toe  Nerve supply: medial plantar nerve  Action: abduction of proximal phalanx of great toe  Flexor Digitorum Brevis  central muscle of 1st layer and is located immediately deep (superior) to plantar aponeurosis  Origin: medial tubercle of calcaneal tuberosity  Insertion: muscle belly gives rise to 4 tendons for lateral 4 toes and tendons split into 2 slips to allow passage of tendons of flexor digitorum longus and slips insert into sides of middle phalanges of lateral 4 toes (similar arrangement to flexor digitorum superficialis in hand)  Nerve supply: medial plantar nerve  Action: flexion of middle and proximal phalanges of lateral 4 toes  Abductor Digiti Minimi  most laterally located in 1st layer  Origin: medial and lateral tubercles of calcaneal tuberosity  Insertion: lateral side of base of proximal phalanx of little toe   Nerve supply: lateral plantar nerve  Action: abduction proximal phalanx of little toe  Second Layer  Lumbricals  4 in number  Origin: tendons of flexor digitorum longus  Insertion: medial side of extensor expansions of lateral 4 toes  Nerve supply: 1st lumbrical = medial plantar nerve; 2nd, 3rd and 4th lumbricals = lateral plantar nerve  Action: flexion of metatarsophalangeal joints and extension of interphalangeal joints of lateral 4 toes  Quadratus Plantae (Flexor Digitorum Accessorius)  Origin: by 2 heads, one from medial surface of calcaneus and the other from lateral border of inferior (plantar) surface of calcaneus  Insertion: posterolateral border of tendon of flexor digitorum longus  Nerve supply: lateral plantar nerve  Action: assists flexor digitorum longus in flexing lateral 4 toes (straightens its line of pull/corrects for obliquity of tendon of flexor digitorum longus)  Tendons of flexor digitorum longus and flexor hallucis longus located in second layer.  Third Layer  Flexor Hallucis Brevis  Origin: cuboid, lateral cuneiform and tendon of tibialis posterior  Insertion: distally, muscle belly divides into 2 heads (medial and lateral) and insert into medial and lateral sides of base of proximal phalanx of great toe and there is a sesamoid bone within tendon of each head  tendon of flexor hallucis longus runs between medial and lateral heads of flexor hallucis brevis  Nerve supply: medial plantar nerve  Action: flexion of proximal phalanx of great toe  Adductor Hallucis  Origin:   oblique head: bases of 2nd, 3rd and 4th metatarsals  transverse head: plantar ligaments of 3rd, 4th and 5th metatarsophalangeal joints  Insertion: lateral side of base of proximal phalanx of great toe  Nerve supply: lateral plantar nerve  Action: adduction of proximal phalanx of great toe; assists in maintaining transverse arch of foot  Flexor Digiti Minimi Brevis  Origin: base of 5th metatarsal  Insertion: lateral side of base of proximal phalanx of little toe  Nerve supply: lateral plantar nerve  Action: flexion of proximal phalanx of little toe  Fourth Layer  Interossei  axis for abduction/adduction of toes passes through 2nd toe  plantar interossei - adductors of toes (PAD)  dorsal interossei - abductors of toes (DAB)  plantar and dorsal interossei also flex metatarsophalangeal joints and extend interphalangeal joints  Plantar Interossei  3 in number  Origin: 3rd, 4th and 5th metatarsals  Insertion: medial side of bases of proximal phalanges of 3rd, 4th and 5th toes and their extensor expansions  Nerve supply: lateral plantar nerve  Dorsal Interossei  4 in number  Origin: each dorsal interosseous originates by 2 heads from sides of 2 adjacent metatarsals  Insertion:  1st and 2nd - medial and lateral sides of base of proximal phalanx of 2nd toe;   3rd and 4th - lateral side of bases of proximal phalanges of 3rd and 4th toes (all dorsal interossei also insert into extensor expansions of corresponding toes)  Nerve supply: lateral plantar nerve  Tendons of tibialis anterior and peroneus tertius are located in the fourth layer. Intrinsic Muscles of the Dorsum of the Foot  Extensor Digitorum Brevis  Origin: anterior part of superior surface of calcaneus  Insertion: muscle belly gives rise to 4 tendons that pass anteriorly and medially over dorsum of foot and most medial tendon inserts into base of proximal phalanx of great toe (this tendon with its proximal muscle belly is sometimes considered a separate muscle into extensor hallucis brevis) and lateral 3 tendons join tendons of extensor digitorum longus for 2nd, 3rd and 4th toes  Nerve supply: deep fibular nerve  Action:  extension of proximal phalanx of great toe  assists extensor digitorum longus in extending 2nd to 4th toes