Muscle actions

Question 1

Facial muscles: Describe the actions of the frontalis, occipitalis, and orbicularis oculi muscles

Answer 1

Frontalis: wrinkles the forehead; lifts the eyebrows
Occipitalis: antagonist to frontalis
Orbicularis oculi: squinting and winking

Question 2

Facial muscles: Describe the actions of the zygomaticus, risorius, and orbicularis oris

Answer 2

Zygomaticus: smiling (pulls the corners of the mouth up)
Risorius: pulls angle of the mouth laterally; synergist to the zygomaticus
Orbicularis oris: puckers the lips (kissing, whistling)

Question 3

Facial muscles: Describe the actions of the mentalis, levator labii superioris, depressor labii inferioris, and genioglossus

Answer 3

Mentalis: protrudes lower lip as in pouting; wrinkles the chin.
Levator labii superioris: elevates the upper lip.
Depressor labii inferioris: pulls the lower lip down as in pouting.
Genioglossus: protrudes the tongue; moves tongue side to side.

Question 4

Name and describe the actions of the muscles from lab lists used for chewing and swallowing.

Answer 4

1) Buccinator: compresses the cheeks; sucking (nursing infants); assists in chewing by directing the food between molars.
2) Temporalis and masseter: elevates the mandible (chewing)

Question 5

Name and describe the actions of the neck muscles from lab lists that move the head. (2)

Answer 5

1) Sternocleidomastoid: flexes the head and neck

2) Trapezius: extension of the head and neck

Question 6

Name and locate the muscles of respiration (from lab) (3)

Answer 6

1) Diaphragm: internal muscle that’s the prime mover for inhalation
2) External intercostals: muscle that elevates (lifts) the ribs that assist inhalation; increase size of thoracic cavity
3) Internal intercostals: muscles depress and retract the ribs for forced expiration; decreases size of thoracic cavity.

Question 7

Name and locate the muscles from lab lists of the abdominal wall and back. (4)

Answer 7

1) Rectus abdominis: flexes the waist as in sit-ups; compresses abdominal viscera for urination, defecation, childbirth, and vomiting.
2) External oblique: most superficial muscle located on lateral abdomen; produces twisting at the waist and compresses abdominal viscera
3) Internal oblique: middle muscle layer on the lateral abdomen; produces twisting at the waist and compresses the abdominal viscera
4) Transverse abdominis: deepest muscle layer on the lateral abdomen; compresses abdominal viscera.

Question 8

Name the origin and insertion of pectoralis major

Answer 8

Origin (medial): clavicle, cartilage of ribs 1-6, sternum

Insertion (lateral): intertubercular groove, sulcus of the humerus

Question 9

Name the origin and insertion of the deltoid

Answer 9

Origin (proximal): clavicle and acromion process of the scapula
Insertion (distal): deltoid tuberosity of the humerus

Question 10

Name the origin and insertion of the latissimus dorsi

Answer 10

Origin (medial): spinous processes of T6-L5, iliac crest, and ribs 9-12
Insertion (lateral): intertubercular groove of the humerus

Question 11

Name the origin and insertion of biceps brachii

Answer 11

Origin (proximal): coracoid process and glenoid cavity of the scapula
Insertion (distal): radial tuberosity

Question 12

Name the origin and insertion of triceps brachii

Answer 12

Origin (proximal): posterior humerus and glenoid cavity of the scapula
Insertion (distal): olecranon process of the ulna

Question 13

Describe the action of the deltoid

Answer 13

Abduction of the arm (prime mover); anterior fibers flex the arm, posterior fibers extend the arm

Question 14

Describe the action of pectoralis major

Answer 14

Flexion and adduction of the arm (prime mover)

Question 15

Describe the action of latissmus dorsi

Answer 15

Extension and adduction of the arm (prime mover)

Question 16

Describe the action of teres major

Answer 16

Synergist to latissimus dorsi

Question 17

Name the 4 rotator cuff muscles and describe their action

Answer 17

As a whole, stabilizes shoulder joint and rotates the humerus.
Supraspinatus
Infraspinatus
Teres minor
Subscapularis

Question 18

Describe the action of serratus anterior and pectoralis minor

Answer 18

Protracts and laterally pulls scapulae forward

Question 19

Describe the action of trapezius and levator scapulae

Answer 19

Elevates scapulae

Question 20

Describe the action of trapezius and latissimus dorsi

Answer 20

Retracts scapulae

Question 21

Describe the action of biceps brachii

Answer 21

Flexion and supination of the forearm

Question 22

Describe the action of brachialis and brachioradialis

Answer 22

Flexion of the forearm

Question 23

Describe the action of the pronator teres

Answer 23

Pronation of the forearm

Question 24

Describe the action of triceps brachii

Answer 24

Extension of the forearm

Question 25

Describe the action of the supinator

Answer 25

Supination of the forearm

Question 26

The flexors of the wrist are located _______, whereas the extensors of the wrist are located ______.

Answer 26

anteriorly; posteriorly

Question 27

Describe the action of the iliopsoas

Answer 27

Flexion of the hip (prime mover)

Question 28

Describe the action of the rectus femoris

Answer 28

Flexion of the hip (synergist)

Question 29

Describe the action of the sartorius

Answer 29

Flexion, abduction, and lateral rotation of the hip; flexion of the knee

Question 30

Describe the action of the tensor fasciae latae

Answer 30

Abduction of the hip

Question 31

Describe the action of the gluteus medius

Answer 31

Abduction of the hip (prime mover)

Question 32

Describe the action of the gluteus maximus

Answer 32

Extension of the hip (prime mover)

Question 33

Describe the actions of the hamstrings and name the muscles involved

Answer 33

Extension of the hip and flexion of the knee
Biceps femoris (lateral)
Semitendonosis (superficial)
Semimembranosus (deep)
Located on posterior thigh

Question 34

Describe the action of the gracilis, abductor longus, and abductor magnus

Answer 34

Adduction of the hip

Question 35

Describe the action of the quadriceps and name the muscles involved

Answer 35

Extension of the knee (all prime movers)
Rectors femoris (front of thigh)
Vastus lateralis (lateral)
Vastus medialis (medial)
Vastus intermedius (deep to rectus femoris)

Question 36

Describe the action of the gastrocnemius

Answer 36

Flexion of the knee

Question 37

Walking on your tiptoes is called _______

Answer 37

plantar flexion

Question 38

Describe the action of the tibialis anterior

Answer 38

Dorsiflexion (prime mover)

Question 39

Describe the action of the gastrocnemius and soleus

Answer 39

Plantar flexion (prime movers)

Question 40

Describe the action of the tibialis posterior

Answer 40

Inversion of the foot (prime mover)

Question 41

Describe the action of the fibularis longus

Answer 41

Eversion of the foot

Question 42

Name the origin and insertion of the gastrocnemius

Answer 42

Origin: medial and lateral condyles of the femur
Insertion: calcaneus