Upper Extremity Muscles

Question 1

Pectoralis major origin

Answer 1

• clavicular head (ant. surface of sternal 1/2 of clavicle)
• sternocostal head (ant. surface of sternum and adjacent superior 6
• aponeurosis of external abdominal oblique

Question 2

Pectoralis major insertion

Answer 2

Common tendon to the lateral lip of the intertubercular groove

Question 3

Pectoralis major action

Answer 3

• adducts and medially rotates humerus

- acting alone: clavicular head flexes humerus, sternocostal head extends it

Question 4

Pectoralis major innervation

Answer 4

• clavicular head: lateral pectoral nerve (C5-6)
• sternocostal head: medial pectoral nerve (C7-T1)
• C7 comes from communicating branch off lateral pectoral n.

Question 5

Pectoralis minor origin

Answer 5

Ribs 3-5 near their costal cartilages

Question 6

Pectoralis minor insertion

Answer 6

Medial border and superior surface of coracoid process of scapula

Question 7

Pectoralis minor action

Answer 7

• stabilizes scapula by pulling it anteriorly and inferiorly against thoracic wall
• minor protractor by moving scapula laterally and anteriorly around thoracic cage

Question 8

Pectoralis minor innervation

Answer 8

Medial pectoral n. (C8-T1)

Question 9

Subclavius origgin

Answer 9

Junction of rib 1 and its costal cartilage

Question 10

Subclavius insertion

Answer 10

Inferior surface of middle 1/3 of clavicle

Question 11

Subclavius action

Answer 11

Draws clavicle medially

Question 12

Subclavius innervation

Answer 12

Nerve to subclavius (C5-6)

Question 13

Serratus anterior origin

Answer 13

• external surfaces of lateral parts of ribs 1-8

- fascia overlying external intercostal muscles

Question 14

Serratus anterior insertion

Answer 14

Anterior surface of medial border of scapula

Question 15

Serratus anterior action

Answer 15

• protracts scapula and holds it against thoracic wall (w/subclavius)
• rotates scapula (pulls on inferior angle of scapula, assists trapezius)

Question 16

Serratus anterior innervation

Answer 16

Long thoracic nerve (C5-7)

Question 17

What are the pectoral muscles?

Answer 17

• pectoralis major
• pectoralis minor
• subclavius
• serratus anterior

Question 18

What are the extrinsic muscles of the back?

Answer 18

• trapezius
• latissimus dorsi
• levator scapulae
• rhomboids

Question 19

Trapezius origin

Answer 19

• medial 1/3 of sup. nunchaku line
• external occipital protuberance
• ligamentum nuchae
• spinous processes C7-12

Question 20

Trapezius insertion

Answer 20

• lateral 1/3 of clavicle, acromion and spine of scapula
• superior fibers extend more laterally
• inferior fibers insert on spine as an aponeurosis (w/out extending to acromion)

Question 21

Trapezius action

Answer 21

• elevates, retracts, and rotates scapula
• superior fibers elevate
• middle fibers retract
• inferior fibers depress
• sup. and inferior fibers act together to superiorly rotate lateral angle

Question 22

Trapezius innervation

Answer 22

Spinal accessory n. (CN XI) and ventral rami of cervical n. (C3-4)

Question 23

Latissimus dorsi origin

Answer 23

• spinous processes of the inferior 6 thoracic vertebrae
• throacolumbar fascia
• iliac crest and ribs 9-12

Question 24

Latissimus dorsi insertion

Answer 24

Floor of intertubercular groove of humerus

Question 25

Latissimus dorsi action

Answer 25

- extends, adducts, and medially rotates the humerus | - raises body towards arms during climbing

Question 26

Levator scapulae origin

Answer 26

Posterior tubercles of transverse processes of C1-4 vertebrae

Question 27

Levator scapulae insertion

Answer 27

Superior part of medial border of scapula

Question 28

Levator scapulae action

Answer 28

Elevates scapula and inferiorly rotates lateral angle of scapula

Question 29

Levator scapulae innervation

Answer 29

- Dorsal scapular n. (C5) | - cervical n. (C3-4)

Question 30

Rhomboid minor origin

Answer 30

- Ligamentum nuchae | - spinous processes of C7-T1

Question 31

Rhomboid major origin

Answer 31

Spinous processes T2-5

Question 32

Rhomboid insertion

Answer 32

Medial border of scapula from level of spine of scapula to inferior angle

Question 33

Rhomboid action

Answer 33

- retracts scapula and inferiorly rotates lateral angle - depresses glenoid cavity - fixes scapula to thoracic wall

Question 34

Rhomboid innervation

Answer 34

Dorsal scapular n. (C4-5)

Question 35

What are the scapular muscles?

Answer 35

- deltoid - supraspinatus - infraspinatus - teres minor - teres major - subscapularis

Question 36

Deltoid origin

Answer 36

Lateral 1/3 of clavicle, acromion, and spine of scapula

Question 37

Deltoid insertion

Answer 37

Deltoid tuberosity of humerus

Question 38

Deltoid action

Answer 38

- ant. part-flexes and medially rotates arm - middle part-abducts arm - post. part-extends and laterally rotates arm

Question 39

Deltoid innervation

Answer 39

Axillary n. (C5-6)

Question 40

Supraspinatus origin

Answer 40

Supraspinous fossa of scapula

Question 41

Supraspinatus insertion

Answer 41

Superior facet of greater tubercle of humerus

Question 42

Supraspinatus action

Answer 42

- Abduct arm (assists deltoid) | - rotator cuff muscle

Question 43

Supraspinatus innervation

Answer 43

Suprascapular n. (C4-6)

Question 44

Infraspinatus origin

Answer 44

Infraspinous fossa of scapula

Question 45

Infraspinatus insertion

Answer 45

Middle facet on reader tubercle of humerus

Question 46

Infraspinatus action

Answer 46

- laterally rotate arm | - rotator cuff muscle helps hold head of humerus in glenoid cavity

Question 47

Infraspinatus innervation

Answer 47

Suprascapular n. (C5-6)

Question 48

Teres minor origin

Answer 48

Superior part of lateral border of scapula

Question 49

Teres minor insertion

Answer 49

Inferior facet on greater tubercle of humerus

Question 50

Teres minor action

Answer 50

- laterally rotate arm | - rotator cuff muscle helps hold head of humerus in glenoid cavity

Question 51

Teres minor innervation

Answer 51

Axillary n. (C5-6)

Question 52

Teres major origin

Answer 52

Dorsal surface of inferior angle of scapula

Question 53

Teres major insertion

Answer 53

Medial lip of intertubercular groove of humerus

Question 54

Teres major action

Answer 54

Adducts and medially rotates arm

Question 55

Teres major innervation

Answer 55

Lower subscapular n. (C5-6)

Question 56

Subscapularis origin

Answer 56

Subscapular fossa

Question 57

Subscapularis insertion

Answer 57

Lesser tubercle of humerus

Question 58

Subscapularis action

Answer 58

- medially rotates and adducts arm | - rotator cuff muscle helps hold head of humerus in glenoid cavity

Question 59

Subscapularis innervation

Answer 59

Upper and lower subscapular n. (C5-7)