Actions_Lower Extremity

Question 1

Psoas Major

Answer 1

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

Question 2

Psoas Minor

Answer 2

Flexion of trunk and lumbar spine

Question 3

Illiacus

Answer 3

Hip flexion

Flexes pelvis on femur

Question 4

Pectineus

Answer 4

Hip adduction

Assist hip flexion

Question 5

Gracilis

Answer 5

Hipp adduction
Knee flexion
MR of knee

Question 6

Adductor Longus

Answer 6

Hip adduction

Assist hip flexion

Question 7

Adductor Brevis

Answer 7

Hip adduction

Hip flexion

Question 8

Adductor Magnus

Answer 8

Hip adduction
May assist hip extension and flexion
Role in hip rotation depends on thigh position

Question 9

Gluteus Maximus

Answer 9

Hip extension
Hip ER
Lower fibers assist hip ADD
Upper fibers assist hip ABD

Question 10

Gluteus Medius

Answer 10

Hip ABD
Hip ER (posterior fibers)
Hip IR (anterior fibers)
Anterior fibers may assist flexion
Posterior fibers may assist extension

Question 11

Gluteus Minimus

Answer 11

Hip ABD

Hip IR

Question 12

Tensor Fascia Latae

Answer 12

Hip flexion
Hip IR
Hip ABD

Question 13

Piriformis

Answer 13

Hip ER
Assist hip ABD when hip is flexed
Assist hip EXT

Question 14

Obturator Internus

Answer 14

Hip ER

Assist hip ABD when hip is flexed

Question 15

Obturator Externus

Answer 15

Hip ER

Assist hip ADD

Question 16

Gemellus Superior

Answer 16

Hip ER

Assist hip ABD when hip is flexed

Question 17

Gemellus Inferior

Answer 17

Hip ER

Assist hip ABD when hip is flexed

Question 18

Quadratus Femoris

Answer 18

Hip ER

Question 19

Biceps Femoris

Answer 19

Knee flexion
Knee ER
Hip extension (long head only)
Assist Hip ER (long head only)

Question 20

Semitendinosus

Answer 20

Knee flexion
Knee IR
Hip extension
Assist hip IR

Question 21

Semimembranosus

Answer 21

Knee flexion
Knee IR
Hip extension
Assist hip IR

Question 22

Sartorius

Answer 22

Hip ER
Hip ABD
Hip flexion
Knee flexion
Knee IR

Question 23

Rectus Femoris

Answer 23

Knee extension

Hip flexion

Question 24

Vastus Lateralis

Answer 24

Knee extension

Question 25

Vastus Intermedius

Answer 25

Knee extension

Question 26

Vastus Medialis (inclues longus and oblique medialis fibers)

Answer 26

Knee extension

Question 27

Articularis Genus

Answer 27

Retracts synovial membrane during knee extension prevent its entrapment between patella and femur

Question 28

Popliteus

Answer 28

``` Knee flexion Knee IR (origin fixed) Hip ER (insertion fixed) ```

Question 29

Tibialis Anterior

Answer 29

Ankle DR | Foot INV

Question 30

Tibialis Posterior

Answer 30

Foot INV | Assist PF

Question 31

Gastrocnemius

Answer 31

Ankle PF Foot INV (supination) Assist knee flexion

Question 32

Soleus

Answer 32

Ankle PF

Question 33

Plantaris

Answer 33

Ankle PF | Assist knee flexion

Question 34

Peroneus Longus

Answer 34

Foot EVE Assist PF Depression of 1st metatarsal

Question 35

Peroneus Brevis

Answer 35

Foot EVE | Assist PF

Question 36

Peroneus Tertius

Answer 36

Ankle DF | Foot EVE

Question 37

Extensor Digitorum Longus

Answer 37

MP extension (of 4 lesser toes) Assist PIP and DIP extension (of lesser toes) Assist ankle DF and eversion

Question 38

Extensor Digitorum Brevis

Answer 38

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)

Question 39

Flexor Digitorum Longus

Answer 39

MP, PIP, DIP flexion of toes 2-5 Assist PF Assist INV

Question 40

Flexor Digitorum Brevis

Answer 40

MP and PIP flexion of toes 2-5

Question 41

Abductor Digiti Minimi

Answer 41

Toe 5 ABD | Toe 5 MP flexion

Question 42

Flexor Digiti Minimi Brevis

Answer 42

Toe 5 MP flexion

Question 43

Quadratus Plantar

Answer 43

DIP flexion of toes 2-5 (in synergy with FDL)

Question 44

Lumbricales

Answer 44

MP flexion of toes 2-5 | Assist PIP and DIP extension of toes 2-5

Question 45

Dorsal Interossei

Answer 45

ABD of toes 2-4 Assist MP flexion of toes 2-4 May assist IP extension of toes 2-4

Question 46

Plantar Interossei

Answer 46

ADD of toes 3, 4, 5 Assist MP flexion of toes 3, 4, 5 May assist IP extension of toes 3, 4, 5

Question 47

Extensor Hallucis Longus

Answer 47

MP and IP extension Assist DF Assist foot INV

Question 48

Flexor Hallucis Longus

Answer 48

Great toe IP flexion Assist great toe MP flexion Assist ankle PF and food INV

Question 49

Flexor Hallucis Brevis

Answer 49

Great toe MP flexion

Question 50

Abductor Hallucis

Answer 50

ABD of great toe Assist great toe MP flexion Assist forefoot ADD

Question 51

Adductor Hallucis

Answer 51

Great toe adduction | Assist great toe MP flexion