muscles in the lower extremities

physci 107

iliopsoas ( iliacus + psoas)

Origin: psoas major: transverse process/bodies of lumbar vertebrae; iliacus: iliac fossa

Insertion: Lesser trochanter

Action: flex hip/torso (more so the psoas major)

gluteus maximuis

origin: ilium, sacrum, coccyx

insertion: gluteal tuberosity of femur

action: extend, abduct, laterally rotate thigh

gluteus medius

origin: ilium

insertion: greater trochanter of femur

action: abduct, medial rotation of thigh

gluteus minimus

origin: ilium

insertion: greater trochanter of femur

action: abduct, medial rotation of thigh

piriformis

under gluteus minimus

tensor fasciae latae and iliotibial band

lateral side of thigh

rectus femoris

origin: anterior inferior iliac spine

insertion: tibial tuberosity via patellar tendon

action: extend knee, flex hip

vastus lateralis

origin: linea aspera

insertion: tibial tuberosity via patellar tendon

action: extend knee

vastus medialis

origin: linea aspera

insertion: tibial tuberosity via patellar tendon

action: extend knee

vastus intermedius

origin: anterior femur

insertion: tibial tuberosity via the patellar tendon

action: extend knee

sartorius

origin: anterior superior iliac spine

insertion: medial proximal tibia

action: flex hip/knee, abduct hip, lateral rotation of thigh

gracilis

origin: inferior ramus of pubis

insertion: medial proximal tibia

action: adduct thigh, flex knee

adductor longus

origin: pubis

insertion: linea aspera

action: adduct/flex thigh, medial rotate thigh

adductor magnus

origin: ischial tuberosity, ischial/pubis rami

insertion: linea aspera, medial supracondylar line, adductor tubercle

action: adduct/flex/extend/medial rotate thigh

biceps femoris (long head and short head)

origin: short head: linea aspera, long head: ischial tuberosity

insertion: head of fibula, proximal lateral tibia

action: flex knee, extend thigh (long head)

semitendonosus

Origin: ischial tuberosity

insertion: proximal medial tibia

action: flex knee, extend thigh

semimembranosus

origin: ischial tuberosity

insertion: proximal medial tibia
action: flex knee, extend thigh

gastrocnemius

origin: medial/lateral condyle of femur

insertion: calcaneal tuberosity via calcaneal tendon

action: plantar flexion, flex knee

soleus

origin: superior tibia, fibula, interouseous membrane

insertion: calcaneal tuberosity via calcaneal tendon

action: plantar flexion

tibialis posterior

deep to soleus

action: inversion/plantar flexion of foot

tibialis anterior

action inversion/dorsiflexion of foot

fibularis (longus and brevis)

action: eversion/ plantar flexion of foot

temporalis

origin: temporal fossa

insertion: coronoid process of mandible

action: elevates mandible

masseter

origin: zygomatic arch

insertion: angle/ramus of mandible

action: elevate mandible, work to move mandible medio-laterally

external oblique

action: trunk flexion, rotate, lateral flexion

internal oblique

action: trunk flexion, rotate, lateral flexion

transverse abdominis

action: compress viscera

rectus abdominis and linea alba

action: flex trunk