12. Lower Extremity Muscles

Question 1

Muscles of the thigh

Answer 1

Hip movers: psoas, iliacus, and gluteus maximus, medius, minimus
Anterior compartment: sartorius, quadriceps, and tensor fasciae latae
Medial compartment: gracilis, and adductor longus, magnus, brevis
Posterior compartment: hamstrings

Question 2

OIA of psoas & iliacus

Answer 2

Origin:
psoas: transverse process of vertebrae
iliacus: iliac fossa of ilium
Insertion: lesser trochanter of femur (as iliopsoas)
Action: flex thigh at hip

Question 3

OIA of gluteus maximus

Answer 3

Origin: iliac crest, sacrum
Insertion: linea aspera and iliotibial band
Action: extend thigh at hip

Question 4

OIA of gluteus medius and minimus

Answer 4

Origin: ilium
Insertion: greater trochanter of femur
Action: abduct thigh at hip and pull center of gravity over foot when walking

Question 5

OIA of Tensor fasciae latae

Answer 5

Origin: iliac crest
Insertion: lateral tibia via iliotibial band
Action: abduct thigh at hip, tenses IT band to stabilize hip and knee joints

Question 6

OIA of sartorius

Answer 6

Origin: anterior superior iliac spine
Insertion: medial tibia (spans two joints)
Action: flexes and laterally rotates thigh at hip, flexes leg at knee

Question 7

OIA of quadriceps

Answer 7

Origin:
rectus femoris: anterior inferior iliac spine
vastus muscles: linea aspera
Insertion: tibial tuberosity via patellar ligament
Action:
rectus femoris: flex thigh at hip and extend leg at knee
vastus muscles: extend leg at knee

Question 8

Types of vastus muscles

Answer 8

Vastus lateralis, vastus intermedius, and vastus medialis

Question 9

OIA of gracilis

Answer 9

Origin: pubis
Insertion: medial, proximal tibia
Action: adduct thigh at hip

Question 10

OIA of Adductor magnus, longus, and brevis

Answer 10

Origin: pubis and ischium
Insertion: linea aspera
Action: adduct thigh at hip

Question 11

Types of hamstrings

Answer 11

Semitendinosus and semimembranosus: medial side of posterior leg
Biceps femoris (long & short head): lateral side of posterior leg

Question 12

OIA of hamstrings

Answer 12

Origin:
semitendinosus, semimembrosus, and long head of biceps femoris: ischial tuberosity
short head of biceps femoris: linea aspera
Insertion:
Semitendinosus and semimembrosus: proximal, medial tibia
biceps femoris: head of fibula
Action: extend thigh at hip, flex leg at knee

Question 13

Muscles of the leg

Answer 13

Anterior compartment: extensors (dorsiflexors) of the foot
Lateral compartment: evertors of the foot
Posterior compartment (superficial & deep): flexors (plantar flexors) of the foot

Question 14

OIA of extensors in the anterior compartment of leg

Answer 14

Origin: tibia & fibula
Insertion: tarsals, metatarsals, and phalanges
Action: dorsiflex and invert foot at ankle, extend toes

Question 15

OIA of evertors in lateral compartment of leg

Answer 15

Origin: fibula
Insertion: metatarsals
Action: evert foot

Question 16

Types of evertors in the leg

Answer 16

Fibularis longus and fibularis brevis

Tendons wrap around lateral malleolus

Question 17

OIA of superficial layer of flexors in posterior compartment of leg

Answer 17

Origin: femoral condyle
Insertion: calcaneus (via calcaneal tendon)
Action: plantarflex foot at ankle

Question 18

Type of superficial layer flexor in the leg

Answer 18

Gastrocnemius is the 2 headed calf muscle

Question 19

OIA of deep layer flexors in posterior compartment of leg

Answer 19

Origin: tibia and fibula
Insertion: tarsals, metatarsals, phalanges
Action: plantarflex foot and toes, invert foot at ankle

Question 20

How does inversion of the foot occur?

Answer 20

Both anterior no posterior compartments of the leg work together

Question 21

Number of intrinsic muscles of the foot

Answer 21

21 muscles in total