ch 3 muscles

Question 1

diaphragm

Answer 1

function:
breathing - exhalation and inhalation by changing vertical dimensions of thoracic cavity

• contraction: flatten and increase vertical dimensions of thoracic cavity-> inhalation
• relaxation: moves superiouly, decrease vertical dimensions of thoracic cavcity -> exhalation

Question 2

serratus anterior

Answer 2

pectoral girdle
function:
- abducts and rotates scapula
- elevates ribs
-“boxer’s muscle” : horizontal arm movements, punching, pushing

Question 3

biceps brachii

Answer 3

upper limb
- flexes forearm at elbow joint
-supinates forward at radioulnar joints
-flexes arm at shoulder joint

Question 3

trapezius

Answer 3

pectoral girdle
function:
- superior fibres upward rotate scapula
-middle fibres adduct scapula
-inferior fibres depress and upward rotate scapula

Question 4

brachioradialis

Answer 4

upper limb
- flexes forearm at elbow joint

Question 5

deltoid

Answer 5

upper limb

• later fibres: abduct arm at shoulder joint
  -anterior fibres: flex and medially rotate arm at shoulder joint
  -posterior fibers: extend and laterally rotate arm at shoulder joint

Question 6

latissimus dorsi

Answer 6

upper limb

• extends, adducts and medially rotates arm at shoulder joint
• draws arm inferiorly and posteriorly

Question 7

pectoralis major

Answer 7

upper limb

• adducts and medially rotates arm at shoulder joint