Dorsal Scapular Muscles

Question 1

Deltoid Action

Answer 1

clavicular (anterior): shoulder flexion and IR
acromial (middle): shoulder abduction
spinal (posterior): shoulder extension and ER

Question 2

Deltoid PA

Answer 2

clavicle, acromion, spine of scapula

Question 3

Deltoid DA

Answer 3

deltoid tuberosity of humerus

Question 4

Deltoid Innervation

Answer 4

axillary nerve (C5, C6)

Question 5

Pectoralis Major Action

Answer 5

• shoulder adduction, IR, horizontal adduction
• draws scapula anteriorly and inferiorly (protraction)
• clavicular head alone: shoulder flexion
• sternocostal head alone: shoulder extension (from flexed position)

Question 6

Pectoralis Major PA

Answer 6

clavicular head: clavicle
sternocostal head: sternum, superior six costal cartilages, external oblique muscle

Question 7

Pectoralis Major DA

Answer 7

lateral lip of intertubercular sulcus of humerus

Question 8

Pectoralis Major Innervation

Answer 8

lateral and medial pectoral nerves
- clavicular head (C5, C6)
- sternocostal head (C7, C8, T1)

Question 9

Pectoralis Minor Action

Answer 9

• stabilizes scapula by drawing it anteriorly and inferiorly against thoracic wall
• (w/ fixed scapula) assists in elevation of thorax during forced inhalation

Question 10

Pectoralis Minor PA

Answer 10

ribs 3-5

Question 11

Pectoralis Minor DA

Answer 11

coracoid process

Question 12

Pectoralis Minor Innervation

Answer 12

medial pectoral nerve (C8, T1), lateral pectoral nerve

Question 13

Infraspinatus Action

Answer 13

shoulder ER (main)
stabilize head of humerus in glenoid cavity

Question 14

Infraspinatus PA

Answer 14

infraspinous fossa of scapula

Question 15

Infraspinatus DA

Answer 15

greater tubercle of humerus

Question 16

Infraspinatus Innervation

Answer 16

suprascapular nerve (C5, C6)

Question 17

Teres Major Action

Answer 17

shoulder extension, adduction, IR

Question 18

Teres Major PA

Answer 18

posterior surface of inferior angle of scapula

Question 19

Teres Major DA

Answer 19

medial lip of intertubercular sulcus of humerus

Question 20

Teres Major Innervation

Answer 20

lower subscapular nerve (C5, C6)

Question 21

Supraspinatus Action

Answer 21

initiates and assists deltoid in shoulder abduction
stabilize head of humerus in glenoid cavity

Question 22

Supraspinatus PA

Answer 22

supraspinous fossa of scapula

Question 23

Supraspinatus DA

Answer 23

greater tubercle of humerus

Question 24

Supraspinatus Innervation

Answer 24

suprascapular nerve (C4, C5, C6)

Question 25

Teres Minor Action

Answer 25

shoulder ER (helper) stabilize head of humerus in glenoid cavity

Question 26

Teres Minor PA

Answer 26

lateral border of scapula

Question 27

Teres Minor DA

Answer 27

greater tubercle of humerus

Question 28

Teres Minor Innervation

Answer 28

axillary nerve (C5, C6)

Question 29

Subscapularis Action

Answer 29

shoulder IR stabilize head of humerus in glenoid cavity

Question 30

Subscapularis PA

Answer 30

subscapular fossa of scapula

Question 31

Subscapularis DA

Answer 31

lesser tubercle of humerus

Question 32

Subscapularis Innervation

Answer 32

upper and lower subscapular nerves (C5, C6, C7)

Question 33

Serratus Anterior Action

Answer 33

scapular protraction, upward rotation holds scapula against thoracic wall

Question 34

Serratus Anterior PA

Answer 34

lateral parts of ribs 1-8/9

Question 35

Serratus Anterior DA

Answer 35

medial border of scapula

Question 36

Serratus Anterior Innervation

Answer 36

long thoracic nerve (C5, C6, C7)