Muscles of Pectoral, Extrinsic and Intrinsic Shoulder

Question 1

Actions of pectoralis major

Answer 1

Adducts UL

Medially rotates UL

Draws scapula anteroinferiorly

Clavicular head - flexes UL

Question 2

Difference in innervation between pectoralis major and minor

Answer 2

Pec Maj - lateral and medial pectoral nerves

Pec minor - medial pectoral nerves

Question 3

Actions of serratus anterior

Answer 3

Protraction of scapula

Upward (lateral) rotation of the scapula - allows arm to be raised over 90o

Holds scapula against ribcage

Question 4

Innervation of serratus anterior

Answer 4

Long thoracic nerve

Question 5

Action of subclavius

Answer 5

Anchors and depresses clavicle

Question 6

Actions of trapezius

Answer 6

Upper fibres

• elevate scapula
• rotate scapula during abduction of arm

Middle fibres
- retracts the scapula

Lower fibres
- pulls scapula inferiorly

Question 7

Innervation of trapezius

Answer 7

Motor = accessory nerve

Question 8

Actions of latissimus dorsi

Answer 8

Extension of UL
Adduction of UL
Medial rotation of UL

Question 9

Innervation of lat dorsi

Answer 9

thoracodorsal nerve

Question 10

Action of levator scapulae

Answer 10

Elevates scapula

Question 11

Innervation of levator scapula, rhomboid major and minor

Answer 11

Dorsal scapular nerve

Question 12

Actions of rhomboids

Answer 12

Retracts and rotates scapula

Question 13

Actions of deltoid

Answer 13

Anterior

• flexion of UL
• medial rotation of UL

Middle
- abductor after 15o

Posterior

• extension of UL
• lateral rotation of UL

Question 14

Innervation of deltoid

Answer 14

Axillary

Question 15

Action of teres major

Answer 15

Adducts shoulder

Medially rotates arm

Question 16

Innervation of teres major

Answer 16

Lower sub scapular nerve

Question 17

Action of supraspinatus

Answer 17

Abducts arm 0-15o

Assists deltoid for rest of abduction

Question 18

Action of infraspinatus

Answer 18

Laterally rotates arm

Question 19

Innervation of supraspinatus and infraspinatus

Answer 19

Suprascapular nerve

Question 20

Action of subscapularis

Answer 20

Medially rotates arm

Question 21

Action of teres minor

Answer 21

Laterally rotates arm

Question 22

Innervation of teres minor

Answer 22

Axillary nerve