Week 4 - Muscles that move the Scapula & Arm

Question 1

What is the function of the main action of the muscles that move the pectoral girdle?

Answer 1

Main action of the muscles that move the pectoral girdle is to stabilise the scapula so it can function as a steady origin for most of the muscles that move the humerus.

Question 2

What are the 2 groups you can class muscles that move the pectoral girdle into?

Answer 2

Based on location:

Anterior thoracic muscles
Posterior thoracic muscles

Question 3

List the anterior thoracic muscles

Answer 3

Subclavius

Pectoralis minor

Serratus anterior

Question 4

Origin + insertion for the subclavius

Answer 4

0 = Rib 1

I = Clavicle

Question 5

Action of the subcalvius

Answer 5

Depresses + moves clavicle anteriorly + helps stabilise pectoral girdle.

Question 6

Origin + insertion for the pectoralis minor

Answer 6

O = Ribs 2-5,3-5 or 2-4.

I = Coracoid process of scapula.

Question 7

Action of the pectoralis minor

Answer 7

Abducts scapula + rotates downwards.

Question 8

Origin + insertion for the serratus anterior

Answer 8

O = Ribs 1-8 or 1-9

I = Vertebral border + inferior angle of scapula

Question 9

Action of serratus anterior

Answer 9

Abducts scapula + rotates upward.

Question 10

List the posterior thoracic muscles

Answer 10

Trapezius

Levator scapulae

Rhomboid major

Rhomboid minor

Question 11

Origin + insertion for the trapezius

Answer 11

O = Superior nuchal line of occipital bone, ligament nuchae + spines of C7-T12.

I = Clavicle + acromion + spine of scapula.

Question 12

Action of trapezius

Answer 12

Superior fibres upward rotate scapula.

Middle fibres adduct scapula.

Inferior fibres depress + upward rotate scapula

Superior + inferior fibres rotate scapula upward

Question 13

Origin + insertion for the levator scapulae

Answer 13

O = Transverse processes of C1-C4.

I = Vertebral border of scapula inferior to spine.

Question 14

Action of the levator scapulae

Answer 14

Elevates scapula + rotates it downward.

Question 15

Origin + insertion for the rhomboid major

Answer 15

O = Spines of T2-T5

I = Vertebral border of scapula inferior to spine

Question 16

Action of rhomboid major

Answer 16

Elevates + adducts scapula + rotates it downward

Question 17

Origin + insertion for the rhomboid minor

Answer 17

O = Spines of C7-T1

I = Vertebral border of scapula superior to spine.

Question 18

Action of rhomboid minor

Answer 18

Elevates + adducts scapula + rotates downward.

Question 19

Define + provide an example for elevation of the scapula

Answer 19

Superior movement of the scapula

i.e shrugging the shoulders or lifting a weight over the head.

Question 20

Define + provide an example for depression of the scapula

Answer 20

Inferior movement of scapula

i.e pulling down on a rope attached to a pulley.

Question 21

Define + provide an example for abduction of the scapula

Answer 21

Movement of the scapula laterally + anteriorly i.e doing a push up or punching.

Question 22

Define + provide an example for adduction of the scapula

Answer 22

Movement of scapula medially + posteriorly I.e pulling the oars in a rowboat.

Question 23

Define + provide an example for upward rotation of the scapula

Answer 23

Movement of inferior angle of scapula laterally so the glenoid cavity is moved upward. — Req. to move the humerus past the horizontal, i.e raising the arms in a jumping jack.

Question 24

Define + provide an example for downward rotation of the scapula

Answer 24

Movement of inferior angle of scapula medially so that the glenoid cavity is moved downward.

i.e when gymnast on parallel bars supports the weight of the body on hands.

Question 25

What 2 categories of muscles move the humerus?

Answer 25

Axial muscles Scapular muscles

Question 26

List the axial muscles that move the humerus

Answer 26

Pectoralis major Latissimus dorsi

Question 27

Origin for the pectoralis major

Answer 27

Clavicle, sternum + cartilages of ribs 2-6 + sometimes ribs 1-7.

Question 28

Insertion for the pectoralis major

Answer 28

Greater tubercle + lateral lip of intertubercular sulcus of humerus.

Question 29

Action of the pectoralis major

Answer 29

Adducts + medially rotates arm at shoulder joint.

Question 30

Origin for latissimus dorsi

Answer 30

Spines of T7-L5 Lumbar vertebrae Crests of sacrum Ilium Ribs 9-12

Question 31

Insertion for latissimus dorsi

Answer 31

Intertubercular sulcus of humerus.

Question 32

Action for latissimus dorsi

Answer 32

Extends, adducts + medially rotates arm at shoulder joint

Question 33

List the scapular muscles that move the humerus

Answer 33

Deltoid Subcapularis Supraspinatus Infraspinatus Teres major Teres minor Coracobrachialis

Question 34

Origin + insertion point for deltoid

Answer 34

O = Acromial extremity of clavicle, acromion of scapula + spine of scapula. I = Deltoid tuberosity of humerus.

Question 35

Action of deltoid

Answer 35

Lateral fibres abduct arm at shoulder. Anterior fibres flex + medially rotate arm at shoulder. Posterior fibres extend + laterally rotate at shoulder.

Question 36

Origin of subscapularis

Answer 36

Subscapular fossa of scapula.

Question 37

Insertion of subscapularis

Answer 37

Lesser tubercle of humerus

Question 38

Action of subscapularis

Answer 38

Medially rotates arm at shoulder

Question 39

Origin of supraspinatus

Answer 39

Supraspinous fossa of scapula

Question 40

Insertion of supraspinatus

Answer 40

Greater tubercle of humerus.

Question 41

Action of supraspinatus

Answer 41

Assists deltoid muscle in abducting arm at shoulder.

Question 42

Origin of infraspinatus

Answer 42

Infraspinous fossa of scapula

Question 43

Insertion of infraspinatus

Answer 43

Greater tubercle of humerus.

Question 44

Action of infraspinatus

Answer 44

Laterally rotates arm at shoulder

Question 45

Origin + insertion of teres major

Answer 45

O = Inferior angle of scapula I = Medial lip of intertubercular sulcus of humerus.

Question 46

Action of teres major

Answer 46

Extends arm at shoulder + assists in adduction + medial rotation of arm at shoulder joint.

Question 47

Origin + insertion of teres minor

Answer 47

O = Inferior lateral border of scapula I = Greater tubercle of humerus.

Question 48

Action of teres minor

Answer 48

Laterally rotates + extends arm at shoulder

Question 49

Origin + insertion of coracobrachialis

Answer 49

O = Coracoid process of scapula I = Middle of medial surface of shaft of humerus

Question 50

Action of coracobrachialis

Answer 50

Flexes + adducts arm at shoulder

Question 51

What muscles are active throughout the entire throwing motion?

Answer 51

Rotator cuff muscles. W/ activity levels peaking during cocking phase = infraspinatus + teres minor provide external rotation + the subscapularis + supraspinatus assist in providing stability to the glenohumeral joint.