Shoulder muscles

Question 1

Pectoralis Major origin

Answer 1

Medial 1/2 of clavicle, anterior manubrium and body of sternum, costal cartilages of ribs 1-6, rectus sheath

Question 2

Pectoralis major insertion

Answer 2

Lateral lip of bicipital groove

Question 3

Pectoralis major innervation and spinal level

Answer 3

Sternal part: medial pectoral C8 T1

Clavicular part: lateral pectoral C5-7

Question 4

Pectoralis major action

Answer 4

Adduction, horizontal adduction, internal rotation of arm

Assists in flexion, assists in extension from fully flexed position, depress and inferiorly rotate scapula

Question 5

Pectoralis minor origin

Answer 5

Ventral aspects of ribs 3-5

Question 6

Pectoralis minor insertion

Answer 6

Coracoid process of scapula

Question 7

Pectoralis minor innervation and spinal level

Answer 7

Medial pectoral
C8 T1
Maybe some lateral C5,6,7

Question 8

Pectoralis minor action

Answer 8

Depresses and protracts shoulder (stabilizes)

Question 9

Subclavius location and action

Answer 9

Runs superolaterally from 1st rib to clavicle and depresses clavicle and stabilizes

Question 10

Serratus anterior origin

Answer 10

Anterolateral surface of ribs 1-9

Question 11

Serratus anterior insertion

Answer 11

Costal surface of medial border of scapula (@inferior angle mainly)

Question 12

Serratus anterior innervation and spinal level

Answer 12

Long thoracic C5,6,7

Question 13

Serratus anterior action

Answer 13

Protracts scapula, assists upward rotation (lower fibers), depression of scapula, medial rotation(superior fibers)
Maintains contact of vertebral border of scapula to thoracic wall preventing a winging

Question 14

Trapezius origin

Answer 14

External occipital protuberance, ligamentum nuchae, spinous processes C1-T12

Question 15

Trapezius insertion

Answer 15

Spine of scapula, Acromion, lateral 1/3 of clavicle

Question 16

Trapezius innervation and spinal level

Answer 16

Cranial nerve 11 (spinal accessory nerve) C3 C4 Rami

Question 17

Trapezius action

Answer 17

Retract/adduction scapula-most important function is elevation of the lateral angle, or upward rotation of the scapula
Upper fibers: elevate and superiorly rotate scapula , side bend neck
Lower fibers: depress and superiorly rotate scapula
Middle fibers: retract scapula

Question 18

Rhomboid major origin

Answer 18

Spine of T1-4

Question 19

Rhomboid major insertion

Answer 19

Medial border of scapula between spine and inferior angle

Question 20

Rhomboid major innervation and spinal level

Answer 20

Dorsal scapular C5 (C4)

Question 21

Rhomboid major action

Answer 21

Retract/adduct scapula, inferiorly rotate and elevate (medial border) and fix media, border of scapula

Question 22

Rhomboid minor origin

Answer 22

Spinous processes of C6 and C7 (lower part of ligamentum nuchae)

Question 23

Rhomboid minor insertion

Answer 23

Base of spine of the scapula (superior aspect)

Question 24

Rhomboid minor innervation and spinal level

Answer 24

Dorsal scapular C5 (C4)

Question 25

Rhomboid minor action

Answer 25

Retract/adduct scapula; also inferiorly rotate ,elevate (primarily medial border) and fix medial border of scapula

Question 26

Levator scapulae origin

Answer 26

Transverse processes C1-4

Question 27

Levator scapulae insertion

Answer 27

Medial border of scapula between superior angle and base of spine

Question 28

Levator scapulae innervation and spinal level

Answer 28

May be part of dorsal scapular C3 and C4

Question 29

Levator scapulae action

Answer 29

Elevate scapula, may tilt neck to same side if scapula is fixed

Question 30

Latissimus dorsi origin

Answer 30

Spinous processes of T7-12, thoracolumbar fascia, posterior 1/3 of iliac crest,lower 4 ribs, inferior angle of scapula

Question 31

Latissimus dorsi insertion

Answer 31

Crest of lesser tubercle (floor of bicipital grooves humerus, anterior angle)

Question 32

Latissimus dorsi innervation and spinal level

Answer 32

Thoracodorsal C6-8

Question 33

Latissimus dorsi action

Answer 33

Adduct, extend, and internally rotate arm- strong depressor and inferior rotator of the shoulder

Question 34

Deltoid origin

Answer 34

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

Question 35

Deltoid insertion

Answer 35

Lateral surface of middle humerus (deltoid tuberosity)

Question 36

Deltoid innervation and spinal level

Answer 36

Axillary C5,6

Question 37

Deltoid action

Answer 37

As a unit: abduct arm Anterior fibers: flex and internal rotate arm, horizontally adduct arm Middle fibers: abduct arm Posterior fibers: extend and externally rotate arm, horizontal abduction

Question 38

Supraspinatus origin

Answer 38

Supraspinatus fossa of scapula

Question 39

Supraspinatus insertion

Answer 39

Superior facet of greater tubercle of humerus

Question 40

Supraspinatus innervation and spinal level

Answer 40

Supracsapular C5,6 (sometimes C4)

Question 41

Supraspinatus action

Answer 41

``` Abduct arm (before deltoid kicks in) Fixes head in humerus (stabilizes) ```

Question 42

Infraspinatus origin

Answer 42

Infraspinatus fossa of scapula

Question 43

Infraspinatus insertion

Answer 43

Middle facet of greater tubercle of humerus

Question 44

Infraspinatus innervation and spinal level

Answer 44

Suprascapular C5,6 (sometime C4)

Question 45

Infraspinatus action

Answer 45

External rotate, assists stabilization of head in humerus

Question 46

Teres minor origin

Answer 46

Upper 2/3 of posterior surface of lateral border of scapula

Question 47

Teres minor insertion

Answer 47

Lower facet of greater tubercle of humerus

Question 48

Teres minor innervation and spinal level

Answer 48

Axillary C5,6

Question 49

Teres minor action

Answer 49

Externally rotate arm, assist in adduction | Note: also active on abduction in order to slide/glide humeral head inferiorly

Question 50

Subscapularis origin

Answer 50

Subscapular fossa

Question 51

Subscapularis insertion

Answer 51

Lesser tubercle of humerus

Question 52

Subscapularis innervation and spinal level

Answer 52

Lower and upper subscapular C 5,6

Question 53

Subscapularis action

Answer 53

Internally rotate arm, stabilization of the G-H joint

Question 54

Teres major origin

Answer 54

Posterior surface of inferior angle of scapula

Question 55

Teres major insertion

Answer 55

Medial lip of bicipital groove (crest of lesser tuberosity)

Question 56

Teres major innervation and spinal level

Answer 56

Lower subscapular C5,6,7

Question 57

Teres major action

Answer 57

Extend (hyper extension) , adduct, internally rotate