Actions_Lower Extremity Flashcards
Psoas Major
Hip flexion (origin fixed)
Trunk flexion (insertion fixed; as in sit-up)
Assist lateral trunk flexion (unilateral action)
May assist hip ER and ABD
With insertion fixed, tightness contributes to increase lordosis
Psoas Minor
Flexion of trunk and lumbar spine
Illiacus
Hip flexion
Flexes pelvis on femur
Pectineus
Hip adduction
Assist hip flexion
Gracilis
Hipp adduction
Knee flexion
MR of knee
Adductor Longus
Hip adduction
Assist hip flexion
Adductor Brevis
Hip adduction
Hip flexion
Adductor Magnus
Hip adduction
May assist hip extension and flexion
Role in hip rotation depends on thigh position
Gluteus Maximus
Hip extension
Hip ER
Lower fibers assist hip ADD
Upper fibers assist hip ABD
Gluteus Medius
Hip ABD Hip ER (posterior fibers) Hip IR (anterior fibers) Anterior fibers may assist flexion Posterior fibers may assist extension
Gluteus Minimus
Hip ABD
Hip IR
Tensor Fascia Latae
Hip flexion
Hip IR
Hip ABD
Piriformis
Hip ER
Assist hip ABD when hip is flexed
Assist hip EXT
Obturator Internus
Hip ER
Assist hip ABD when hip is flexed
Obturator Externus
Hip ER
Assist hip ADD
Gemellus Superior
Hip ER
Assist hip ABD when hip is flexed
Gemellus Inferior
Hip ER
Assist hip ABD when hip is flexed
Quadratus Femoris
Hip ER
Biceps Femoris
Knee flexion
Knee ER
Hip extension (long head only)
Assist Hip ER (long head only)
Semitendinosus
Knee flexion
Knee IR
Hip extension
Assist hip IR
Semimembranosus
Knee flexion
Knee IR
Hip extension
Assist hip IR
Sartorius
Hip ER Hip ABD Hip flexion Knee flexion Knee IR
Rectus Femoris
Knee extension
Hip flexion
Vastus Lateralis
Knee extension
Vastus Intermedius
Knee extension
Vastus Medialis (inclues longus and oblique medialis fibers)
Knee extension
Articularis Genus
Retracts synovial membrane during knee extension prevent its entrapment between patella and femur
Popliteus
Knee flexion Knee IR (origin fixed) Hip ER (insertion fixed)
Tibialis Anterior
Ankle DR
Foot INV
Tibialis Posterior
Foot INV
Assist PF
Gastrocnemius
Ankle PF
Foot INV (supination)
Assist knee flexion
Soleus
Ankle PF
Plantaris
Ankle PF
Assist knee flexion
Peroneus Longus
Foot EVE
Assist PF
Depression of 1st metatarsal
Peroneus Brevis
Foot EVE
Assist PF
Peroneus Tertius
Ankle DF
Foot EVE
Extensor Digitorum Longus
MP extension (of 4 lesser toes)
Assist PIP and DIP extension (of lesser toes)
Assist ankle DF and eversion
Extensor Digitorum Brevis
MP extension of toes 2 to 4
Assist IP extension of toes 2 to 4
MP extension of great toe (via its most medial slip of tendon, also called extensor hallucis brevis; no slip to 5th toed from EDBr)
Flexor Digitorum Longus
MP, PIP, DIP flexion of toes 2-5
Assist PF
Assist INV
Flexor Digitorum Brevis
MP and PIP flexion of toes 2-5
Abductor Digiti Minimi
Toe 5 ABD
Toe 5 MP flexion
Flexor Digiti Minimi Brevis
Toe 5 MP flexion
Quadratus Plantar
DIP flexion of toes 2-5 (in synergy with FDL)
Lumbricales
MP flexion of toes 2-5
Assist PIP and DIP extension of toes 2-5
Dorsal Interossei
ABD of toes 2-4
Assist MP flexion of toes 2-4
May assist IP extension of toes 2-4
Plantar Interossei
ADD of toes 3, 4, 5
Assist MP flexion of toes 3, 4, 5
May assist IP extension of toes 3, 4, 5
Extensor Hallucis Longus
MP and IP extension
Assist DF
Assist foot INV
Flexor Hallucis Longus
Great toe IP flexion
Assist great toe MP flexion
Assist ankle PF and food INV
Flexor Hallucis Brevis
Great toe MP flexion
Abductor Hallucis
ABD of great toe
Assist great toe MP flexion
Assist forefoot ADD
Adductor Hallucis
Great toe adduction
Assist great toe MP flexion