Muscles of Pectoral Region

Question 1

pectoralis major muscle is the most _______ and extends _____ to form __________

Answer 1

superficial muscle
laterally
anterior wall of axilla

Question 2

2 heads of pectoralis major

Answer 2

clavicular head - originates from clavicle
sternocostal head - larger and originates from:
CAS
1. 1/2 anterior surface of sternum
2. front of upper 6 costal cartilages
3. aponeurosis

Question 3

insertion of pectoralis major muscle

Answer 3

inserted by bilaminar tendon into intertubercular groove of humerus

Question 4

insertion of pectoralis major muscle - HOW?

Answer 4

anterior lamina - formed by clavicular head
posterior lamina - formed by sternocostal head
the 2 are continuous and form a U

Question 5

The twisting of the lower border of the tendon forms the

Answer 5

anterior axillary fold

Question 6

nerve supply of pectoralis major

Answer 6

lateral and medial pectoral nerves

Question 7

Action of pectoralis major

1. As a whole
2. Clavicular Head
3. Sternocostal Head

Answer 7

1. As a whole, the muscle adducts (moves) and medially rotates the arm
2. Clavicular head flexes arm
3. Sternocostal head extends flexed arm

Question 8

In what action is the pectoralis major used

Answer 8

swimming, rowing, climbing

Question 9

origin of pectoralis minor

Answer 9

outer surfaces of 3rd, 4th, 5th ribs near their costal cartilages

Question 10

insertion of pectoralis minor

Answer 10

into medial border and upper surface of coracoid process

Question 11

nerve supply of pect. minor

Answer 11

medial pectoral nerve

Question 12

action of pectoralis minor

Answer 12

1. protraction of shoulder girdle
2. depression of shoulder
3. fixed scapula, raises ribs in forced inspiration

Question 13

location of pectoralis minor

Answer 13

deep to middle part of pectoralis major

Question 14

location of subclavius

Answer 14

slender muscle present just below clavicle

Question 15

origin of subclavius

Answer 15

from upper surface of 1st costo chondral junction

Question 16

insertion of subclavius

Answer 16

into groove on lower surface of middle third of clavicle

Question 17

nerve supply of subclavius

Answer 17

nerve to subclavius (C5)

Question 18

action of subclavius

Answer 18

fixes the clavicle thus preventing excessive movement of shoulder girdle