Shoulder Muscles

Question 1

Trapezius

Answer 1

O- Upper- External occipital protuberance, nuchal line, nucha ligaments, Sps C2-C7
Middle- SPs T1-T6
Lower- SPs T7-T12

I- Spine of the scapula, acromion, lateral 1/3 of clavicle

A- Upper: Scapular elevation
Middle: Retraction
Lower: Scapular Depression, Posterior scapular tilt

N- Spinal Accessory Nerve

Question 2

Latissimus Dorsi

Answer 2

O: SPs of T7-T12, Last 4 ribs, thoraco-lumbar fascia, posterior iliac crest and inferior angle of the scapula

I: Medial lip of bicipital groove, lesser tubercle of humerus

A: Hip Stability, Extension, Adduction, medial rotation of humerus and tensions thoracolumbar fascia, lumbar extension and ipsilateral lateral flexion

N: Thoracodorsal Nerve

Question 3

Levator Scapula

Answer 3

O: TVPs C1-C4

I: Superior angle of the scapula

A: Ipsilateral cervical flexion, scapular elevation, rotates the superior angle medially and inferior

N: Dorsal Scapular Nerve

Question 4

Rhomboid Major/Minor

Answer 4

O- Major (lower)- SPs T2-T5 and Minor (higher)- SPs C7-T1

I- Major: Medial scapular border, inferior angle of scapula
Minor: Root of spine of scapula, medial border of scapula

A- Retracts scapula, adducts scapula, downward rotation of scapula

N- Dorsal Scapular Nerve

Question 5

Serratus Anterior

Answer 5

O- Fleshy slips of ribs 1-9 (external oblique fibers)

I- Anterior medial border of scapula

A- Protracts scapula, upward rotation of the scapula

N- Long Thoracic Nerve

Question 6

Pectoralis Minor

Answer 6

O- Ribs 3-5

I- Coracoid Process

A- Elevates scapula on respiration, anteriorly tilts superior aspect of the scapula

N- Medial Pectoral Nerve

Question 7

Pectoralis Major

Answer 7

O- Clavicular Head- Anterior medial 1/2 of clavicle
Sternocostal Head- Anterior surface of sternum, external oblique aponeurosis, ribs 1-6, costochondral joints 1-6

I- Lateral aspect of the bicipital groove

A- Clavicular head- Flexion, adduction and internal rotation humerus
Sternocostal head- Extension, adduction and external rotation of humerus

N- Medial and Lateral Pectoral Nerve

Question 8

Subclavius

Answer 8

O- 1st rib and costal chondral cartilage

I- Subclavian groove of the clavicle

A- Depression and internal rotation of clavicle

N- Nerve to Subclavius

Question 9

Deltoid

Answer 9

O- Anterior: Lateral 1/3 of the clavicle
Middle: Acromion Process
Posterior: Lateral 1/3 of the spine of the scapula

I- Deltoid tuberosity of the humerus

A- Anterior- Horizontal adduction, internal rotation, flexion of the humerus
Middle- Abduction of the humerus
Posterior- Horizontal abduction, external rotation, extension of the humerus

N- Axillary Nerve

Question 10

Coracobrachialis

Answer 10

O- Coracoid Process

I- Proximal medial 1/3 of humerus

A- Adduction of the humerus, flexion of the humerus (in a weak way)

N- Musculocutaneous Nerve

Question 11

Supraspinatus

Answer 11

O- Supraspinous fossa

I- Most superior aspect of greater tubercle

A- Abduction of humerus (first 30 degrees)

N- Suprascapular nerve

Question 12

Infraspinatus

Answer 12

O- Infraspinous fossa

I- Greater tubercle of humerus

A- External Rotation of the Humerus

N- Suprascapular nerve

Question 13

Teres Major

Answer 13

O- Inferior angle of the scapula

I- Medial lip of the bicipital groove (common insertion with lat)

A- Extension, adduction and internal rotation of humerus

N- Lower subscapular nerve

Question 14

Subscapularis

Answer 14

O-Subscapular Fossa

I- Lesser Tubercle of the humerus

A- Internal Rotation of humerus

N- Upper and Lower Subscapular Nerve

Question 15

Teres Minor

Answer 15

O- Inferior 1/3 of the lateral border of the scapula

I- Greater tubercle of the humerus

A- External Rotation of the humerus (at 45 degrees of abduction)

N- Axillary Nerve