TrunkTrunk

Erector spinaeErector spinae

OriginSacrum; ribs;

lumbar, thoracic, and cervical

vertebrae

Actions:• Extension, rotation, and lateral flexion of

vertebrae.

• Provides resistance that helps control the action of bending over

at the waist.

InsertionRibs, thoracic and cervical vertebrae, and skull

IliopsoasIliopsoas

OriginLumbar vertebrae

and iliac bone

InsertionLesser trochanter

of femur

Actions:• Hip flexion

• Spine rotation

• Keeps upper body from falling over when standing

erect.

FootFoot

Tibialis anteriorTibialis anterior

OriginProximal tibia

InsertionFirst cuneform and first metatarsal of foot

Actions:• Dorsiflexion of foot

• Eversion of foot

• Stabilization of ankle

GastrocnemiusGastrocnemius

Actions:• Plantar flexion

• Flexion of the knee

OriginPosterior surface of

distal head of femur

InsertionPosterior surface of

calcaneus

SoleusSoleus

OriginProximal tibia and fibula

InsertionCalcaneus

Actions:• Plantar flexion

Tibialis posteriorTibialis posteriorOriginInner posterior borders of tibia and fibula

InsertionNavicular, first and third cuneforms, cuboid, and second, third, and fourth metatarsals

Actions:• Dorsiflexion of foot

• Eversion of foot

• Stabilization of ankle