Lab 10

Question 1

What is the action of the Iliacus muscle? (hip and thigh)

Answer 1

Flexes thigh or flexes trunk on thigh.

Question 2

What is the action of the Psoas major muscle? (hip and thigh)

Answer 2

Flexes thigh or flexes trunk on thigh; lateral flexion of vertebral column.

Question 3

What is the action of the Sartorius muscle? (hip and thigh)

Answer 3

Flexes, abducts, and laterally rotates thigh and weakly flexes knee joint to achieve cross-legged position.

Question 4

What is the action of the Adductor magnus muscle? (hip and thigh)

Answer 4

Anterior - flexes, adducts, medially rotates thigh.

Posterior - extends thigh.

Question 5

What is the action, origin, and insertion of the Rectus femoris (quadriceps) muscle? (hip and thigh)

Answer 5

Action = extends leg, flexes thigh at hip.

Origin = anterior inferior iliac spine of coxal bone.

Insertion = Patella and tibial tuberosity via patellar ligament.

Question 6

What is the action of the vastus lateralis (quadriceps) muscle? (hip and thigh)

Answer 6

extends and stabilizes leg

Question 7

What is the action of the vastus medialis (quadriceps) muscle? (hip and thigh)

Answer 7

extends leg

Question 8

What is the action of the vastus intermedius (quadriceps) muscle? (hip and thigh)

Answer 8

extends leg

Question 9

What is the action, origin, and insertion of the gluteus maximus muscle? (hip and thigh)

Answer 9

Action = extends thigh (with power as in climbing or running), laterally rotates and abducts thigh.

Origin = sacrum, coccyx, dorsal ilium of coxal bone.

Insertion = gluteal tuberosity of femur, iliotibial tract.

Question 10

What is the action, origin, and insertion of the gluteus medius muscle? (hip and thigh)

Answer 10

Action = abducts and medially rotates thigh (maintains the pelvis level when walking).

Origin = superior lateral surface of ilium.

Insertion = greater trochanter of femur.

Question 11

What is the action, origin, and insertion of the biceps femoris (hamstrings) muscle? (hip and thigh)

Answer 11

Action = extends thigh; flexes and laterally rotates leg.

Origin = long head - ischial tuberosity of coxal bone.
short head - linea aspera of femur.

Insertion = head of fibula, lateral condyle of tibia.

Question 12

What is the action of the semimembranosus (hamstrings) muscle? (hip and thigh)

Answer 12

extends thigh; flexes and medially rotates leg.

Question 13

What is the action of the semitendinosus (hamstrings) muscle? (hip and thigh)

Answer 13

extends thigh; flexes and medially rotates leg.

Question 14

What is the action of the tibialis anterior muscle? (of the lower leg)

Answer 14

dorsiflexion and inversion of foot.

Question 15

What is the action of the extensor digitorum longus muscle? (of the lower leg)

Answer 15

extends toes (metatarsophalangeal joints), dorsiflexion of foot.

Question 16

What is the action of the fibularis longus muscle? (of the lower leg)

Answer 16

plantar flexion and eversion of foot.

Question 17

What is the action, origin, and insertion of the Gastrocnemius muscle? (of the lower leg)

Answer 17

Action = plantar flexion of foot (when leg is extended); flexes knee (when foot is dorsiflexed).

Origin = medial and lateral condyles of femur.

Insertion = calcaneus (via calcaneal tendon).

Question 18

What is the action of the soleus muscle? (of the lower leg)

Answer 18

plantar flexion of foot

Question 19

What is the action of the flexor digitorum longus muscle? (of the lower leg)

Answer 19

plantar flexion and inversion of foot; flexes toes.