Shoulder Muscles

Question 1

Origin of the Deltoid

Answer 1

Lateral 1/3 of clavicle
Acromion
Lower lip of the crest of the scapular spine

Question 2

Insertion of Deltoid

Answer 2

Deltoid tuberosity of humerus

Question 3

Action of Deltoid

Answer 3

Abducts arm
Anterior fibers: Flex & medially rotate arm
Posterior fibers: Extend and laterally rotate arm

Question 4

Origin of Infraspinatus

Answer 4

Infraspinatus fossa

Question 5

Insertion of Infraspinatus

Answer 5

Greater tubercle of humerus (middle facet)

Question 6

Action of Infraspinatus

Answer 6

Laterally rotates arm

Question 7

Origin of Latissimus Dorsi

Answer 7

SP’s T7-L5
Posterior 1/3 of iliac crest
Lower 3-4 ribs
(sometimes from inferior angle of scap)

Question 8

Insertion of Latissimus Dorsi

Answer 8

Floor of Intertubercular Groove

Question 9

Action of Latissimus Dorsi

Answer 9

Extends and rotates arm medially

Question 10

Origin of Levator Scapulae

Answer 10

TVP’s C1-4

Question 11

Insertion of Levator Scapulae

Answer 11

Medial border of scapula from the superior angle of the spine

Question 12

Action of Levator Scapulae

Answer 12

Elevates Scapula

Question 13

Origin of Pectoralis Major

Answer 13

Medial 1/2 of the clavicle
Manubrium & body of sternum
Costal cartilage of ribs 2-6
(Sometimes from the rectus sheath of the upper abdominal wall

Question 14

Insertion of Pectoralis Major

Answer 14

Crest of greater tubercle of humerus

Question 15

Action of Pectoralis Major

Answer 15

Flexes, medially rotates and adducts the arm

Question 16

Origin of Pectoralis Minor

Answer 16

Ribs 3-5

Question 17

Insertion of Pectoralis Minor

Answer 17

Coracoid process of scapula

Question 18

Action of Pectoralis Minor

Answer 18

Draws the scapula forward, medial and downward

Question 19

Origin of Rhomboids Major

Answer 19

SP’s of T2-5

Question 20

Origin of Rhomboids Minor

Answer 20

SP’s of C7-T1
Inferior end of nuchal ligament

Question 21

Insertion of Rhomboids Major

Answer 21

Medial border of scapula inferior to scapular spine

Question 22

Insertion of Rhomboids Minor

Answer 22

Medial border of scapula at the root of scapular spine

Question 23

Action of Rhomboids Major

Answer 23

Retracts, elevates and rotates scapula inferiorly

Question 24

Actions of Rhomboids minor

Answer 24

Retracts, elevates and rotates scapula inferiorly

Question 25

Origin of Serratus Anterior

Answer 25

Ribs 1-8/9

Question 26

Insertion of Serratus Anterior

Answer 26

Medial border of scapula on its costal surface

Question 27

Action of Serratus Anterior

Answer 27

Draws scapula forward, inferior fibers rotate scapula superiorly

Question 28

Insertion of Subclavius

Answer 28

Inferior surface of clavicle

Question 29

Origin of Subclavius

Answer 29

1st rib and its cartilage

Question 30

Action of Subclavius

Answer 30

Draws clavicle (hence shoulder) down and forward

Question 31

Origin of subscapularis

Answer 31

Subscapular fossa

Question 32

Insertion of subscapularis

Answer 32

Lesser Tubercle of humerus

Question 33

Action of Subscapularis

Answer 33

Medially rotates arm ; assists extension of arm

Question 34

Origin of Supraspinatus

Answer 34

Supraspinatus fossa

Question 35

Insertion of Supraspinatus

Answer 35

Greater tubercle of humerus (highest facet)

Question 36

Action of Supraspinatus

Answer 36

Abducts the arm (initiates abduction)

Question 37

Origin of Teres Major

Answer 37

Dorsal surface of the inferior angle of the scapula

Question 38

Insertion of Teres Major

Answer 38

Crest of the lesser tubercle of humerus

Question 39

Action of Teres Major

Answer 39

Adducts and medially rotates arm ; assists in extension (lats little help)

Question 40

Origin of Teres Minor

Answer 40

Upper 2/3 of lateral border of scapula

Question 41

Insertion of Teres Minor

Answer 41

Greater tubercle of humerus (lower facet)

Question 42

Action of Teres Minor

Answer 42

Laterally rotates arm

Question 43

Origin of Trapezius

Answer 43

Medial 1/3 of superior nuchal line External occipital protuberance Nuchal ligament SP's C7-T12

Question 44

Insertion of Trapezius

Answer 44

Lateral 1/3 of clavicle Medial side of acromion Upper crest of scapular spine Tubercle of scapular spine

Question 45

Action of Trapezius

Answer 45

Elevates and depresses scapula (depending on what part of muscle is contracting) Rotates scapula superiorly Retracts scapula