Lower Extremity

Rectus femoris-Action

Extend the knee, flex the hip

Rectus femoris O,I,N

O: anterior inferior iliac spine

I: tibial tuberosity (via patella + patellar ligament)

N: femoral

Vastus medialis-Action

Extend the knee

Vastus medialis O,I,N

O: medial lip of linea aspera

I: tibial tuberosity

N: femoral

Vastus lateralis-Action

Extend the knee

Vastus lateralis O,I,N

O: lateral lip of linea aspera, gluteal tuberosity, greater trochanter

I: tibial tuberosity

N: femoral

Vastus intermedius-Action

Extend the knee

Vastus intermedius O,I,N

O: anterior and lateral shaft of the femur

I: tibial tuberosity

N: femoral

Biceps femoris-Action

Flex the knee, laterally rotate flexed knee

Long head: extend the hip

Short head: assist to laterally rotate the hip, tilt the pelvis posteriorly

Biceps femoris O,I,N

O: ischial tuberosity (long head), lateral lip of linea aspera (short head)

I: head of the fibula

N: sciatic

Semitendinosus-Action

Flex the knee, medially rotate the flexed knee, extend the hip, assist to medially rotate the hip, tilt pelvis posteriorly

Semitendinosus O,I,N

O: ischial tuberosity

I: proximal, medial shaft of the tibia at pes anserinus tendon

N: sciatic

Semimembranosus-Action

Flex the knee, medially rotate flexed knee, extend the hip, assist to medially rotate the hip, tilt the pelvis posteriorly

Semimembranosus O,I,N

O: ischial tuberosity

I: posterior aspect of medial condyle of tibia

N: sciatic

Gastrocnemius-Action

Flex the knee, plantar flex ankle

Gastrocnemius O,I,N

O: condyles of femur (posterior surfaces)

I: calcaneus via calcaneal tendon

N: tibial

Soleus-Action

Plantar flex the ankle

Soleus O,I,N

O: soleal line; proximal posterior surface of tibia, posterior aspect of fibular head

I: calcaneus via calcaneal tendon

N: tibial

Plantaris-Action

weak plantar flexion of ankle, weak flexion of the knee

Plantaris O,I,N

O: lateral supracondylar line of femur

I: calcaneus via calcaneal tendon

N: tibial

Popliteus-Action

medially rotate flexed knee, flex knee

Popliteus O,I,N

O: lateral condyle of femur

I: proximal posterior aspect of tibia

N: tibial

Fibularis Longus-Action

evert foot, assist ankle plantar flexion

Fibularis Longus O,I,N

O: head of fibula and proximal 2/3 of lateral fibula

I: base of 1st metatarsal and medial cuneiform

N: superficial fibular

Fibularis (peroneus) Brevis-Action

evert foot, assist ankle plantar flexion

Fibularis Brevis O,I,N

O: distal 2/3 of lateral fibula

I: tuberosity of 5th metatarsal

N: superficial fibular

Fibularis Tertius (rare)

Found anterior to lateral malleolus

Short branch of extensor digitorum longus

Attaches on tuberosity of 5th metatarsal

Tibilalis Anterior-Action

Invert foot, dorsiflex ankle

Tibialis Anterior O,I,N

O: lateral condyle of tibia, proximal lateral surface of tibia, interosseous membrane

I: medial cuneiform and base of 1st metatarsal

N: deep fibular

Extensor Digitorum Longus-Action

extend 2-5th toes, dorsiflex ankle, evert foot

Extensor Digitorum Longus O,I,N

O: lateral condyle of tibia, proximal anterior shaft of fibula, interosseous membrane

I: middle and distal phalanges of 2-5th toes

N: deep fibular

Extensor Hallicus Longus-Action

extend 1st toe, dorsiflex ankle, invert foot

Extensor Hallicus Longus O,I,N

O: middle, anterior surface of fibula and interosseous membrane

I: distal phalanx of first toe

N: deep fibular

Tibialis Posterior-Action

invert foot, plantar flex ankle

Tibialis Posterior O,I,N

O: proximal posterior shafts of tibia and fibula, interosseous membrane

I: all 5 tarsal bones, bases of 2-5th metatarsals

N: tibial

Flexor Digitorum Longus-Action

flex 2-5th toes, weak plantar flexion of ankle, invert foot

Flexor Digitorum Longus O,I,N

O: middle posterior surface of tibia

I: distal phalanges of 2-5th toes

N: tibial

Flexor Hallicus Longus-Action

flex 1st toe, weak plantar flexion of ankle, invert foot

Flexor Hallicus Longus O,I,N

O: middle half of posterior fibula

I: distal phalanx of first toe

N: tibial

Extensor Digitorum Brevis-Action

extend 2-4th toes

Extensor Digitorum Brevis O,I,N

O: dorsal surface of calcaneus

I: 2-4th toes via extensor digitorum longus tendons

N: deep fibular

Flexor Digitorum Brevis-Action

flex middle phalanges of 2-5th toes

Flexor Digitorum Brevis O,I,N

O: medial process of calcaneus and plantar aponeurosis

I: middle phalanges of 2-5th toes

N: tibial

Abductor Hallucis-Action

abduct first toe, assist to flex first toe

Abductor Hallucis O,I,N

O: medial process of calcaneus and plantar aponeurosis

I: proximal phalanx of first toe and medial sesamoid bone

N: tibial

Abductor Digiti Minimi-Action

flex 5th toe, assist to abduct 5th toe

Abductor Digiti Minimi O,I,N

O: lateral process of calcaneus and plantar aponeurosis

I: proximal phalanx of 5th toe

N: tibial

Extensor Hallucis Brevis-Action

extend 1st toe

Extensor Hallucis Brevis O,I,N

O: dorsal surface of calcaneus

I: proximal phalanx of 1st toe

N: deep fibular

Flexor Hallucis Brevis-Action

flex 1st toe

Flexor Hallucis Brevis O,I,N

O: plantar surfaces of cuboid and lateral cuneiform

I: medial and lateral surfaces of base of proximal phalanx of first toe

N: tibial

Adductor Hallucis-Action

adduct 1st toe, assist to maintain transverse arch of foot, assist to flex 1st toe

Adductor Hallucis O,I,N

O: bases of 2-4th metatarsals (oblique head), plantar ligament of 3-5th metatarsophalangeal joints (transverse head)

I: lateral surface of base of proximal phalanx of 1st toe

N: tibial

Flexor Digiti Minimi Brevis-Action

flex 5th toe

Flexor Digiti Minimi Brevis O,I,N

O: base of 5th metatarsal

I: base of proximal phalanx of 5th toe

N: tibial

Quadratus Plantae-Action

assist flexor digitorum longus to flex 2-5th toes

Quadratus Plantae O,I,N

O: medial and lateral sides of plantar surface of calcaneus

I: posterior lateral aspect of flexor digitorum longus tendon

N: tibial

Plantar Interossei-Action

adduct 3-5th toes

Plantar Interossei O,I,N

O: medial surface of 3-5th metatarsals

I: medial surfaces of proximal phalanges of 3-5th toes

N: tibial

Dorsal Interossei-Action

abduct 2-4th toes, flex 2-4th toes

Dorsal Interossei O,I,N

O: adjacent surfaces of all metatarsals

I: medial surface of proximal phalanx of 2nd toe (first), lateral surfaces of proximal phalanges of 2-4th toes (2-4th)

N: tibial

Lumbricals - Action

flex proximal phalanges of 2-5th toes at metatarsophalangeal joints, extend middle and distal phalanges of 2-5th toes at IP joints

Lumbricals of Foot O,I,N

O: tendons of flexor digitorum longus

I: bases of proximal phalanges of 2-5th toes and extensor digitorum longus tendons

N: tibial