Pectoral region muscles

Question 1

Pectoralis major origin

Answer 1

• clavicular head originates from anterior surface of medial half of clavicle.
• sternocostal head originates from sternum, superior 6 costal cartilages and aponeurosis of external oblique

Question 2

pectoralis major insertion

Answer 2

• both heads insert into lateral lip of bicipital groove.

Question 3

pectoralis major innervation

Answer 3

• clavicular head; lateral pectoral nerve arising from lateral cord of brachial plexus. roots C5, C6 and C7
• sternocostal head; medial pectoral nerve arising from medial cord of brachial plexus, roots C8-T1

Question 4

pectoralis major functions

Answer 4

• adduction
• medial rotation
• flexion at shoulder (clavicular head)
• extension at shoulder (sternal costal head - also the prime mover of pushups)

Question 5

pectoralis minor origin

Answer 5

3rd to 5th ribs

Question 6

pectoralis minor insertion

Answer 6

coracoid process of scapula

Question 7

pectoralis minor innervation

Answer 7

• medial pectoral nerve roots C8, T1

Question 8

pectoralis minor functions

Answer 8

• stabilises scapula, pulls it against thoracic wall
• protraction of scapula (reaching forward or pushing)
• assists in 3rd, 4th and 5th rib elevation during forced inhalation, increasing thoracic cavity volume

Question 9

Serratus anterior origin

Answer 9

upper 8 ribs

Question 10

serratus anterior insertion

Answer 10

• superior part into superior angle of scapula
• intermediate inserts into medial border
• inferior part inserts into medial border and inferior angle

Question 11

serratus anterior innervation

Answer 11

• long thoracic nerve roots C5-C7 of brachial plexus

Question 12

serratus anterior functions

Answer 12

• holds scapula against rib cage at rest
• pulls scapula forward and around thorax during protraction
• rotates scapula, allows arms to be raised above 90 degrees

Question 13

subclavius origin

Answer 13

• junction of 1st rib and its costal cartilage

Question 14

suclavius insertion

Answer 14

• subclavian groove on inferior surface of clavicle

Question 15

subclavius innervation

Answer 15

• subclavian nerve C5-C6 (small branch arising from superior trunk of brachial plexus)

Question 16

subclavius functions

Answer 16

• depresses lateral clavicle active stabilisation of clavicle during shoulder and arm movements