Shoulder Muscles

Question 1

Trapezius

Answer 1

O - Superior nuchal line & external occipital protuberance, ligamentum nuchae, C7-T12 spinous processes

I - Clavicle lateral 1/3, Scapular acromion & spine

N - Motor: accessory nerve (XI) & Proprioception: C3-C4

A - scapula elevation, retraction, depression and rotation to abduct arm above horizontal; neck extension

Question 2

Deltoid

Answer 2

O - Clavicle lateral 1/3, Scapular acromion & spine
I - Deltoid tuberosity of Humerus
N - Axillary nerve (C5, C6)
A - shoulder abduction past 15°, anterior part: shoulder flexion & medial
rotation, posterior part: shoulder extension & lateral rotation

Question 3

Levator Scapulae

Answer 3

O - C1-C4 transverse processes
I - superior angle of scapula
N - C3-C4 & dorsal scapular nerve (C5)
A - Scapula elevation

Question 4

Rhomboid Minor

Answer 4

O - C7-T1 spinous processes
I - Vertebral border of scapula near spine
N - Dorsal scapular nerve (C4, C5)
A - Scapula elevation & retraction

Question 5

Rhomboid Major

Answer 5

O - T2-T5 spinous processes
I - Vertebral border of scapula from spine to inferior angle rhomboid minor & major
N - Dorsal scapular nerve (C4, C5)
A - Scapula elevation & retraction

Question 6

Rotator cuff muscles (4)

Answer 6

Supraspinatus
Teres minor
Infraspinatus
Subscapularis

Question 7

Supraspinatus

Answer 7

O - Supraspinous fossa of scapula
I - Superior facet of greater tubercle of Humerus
N - suprascapular nerve (C5, C6)
A - Initiate shoulder abduction

Question 8

Infraspinatus

Answer 8

O - Infraspinous fossa of scapula
I - Middle facet of greater tubercle of humerus
N - Suprascapular nerve (C5, C6)
A - External rotation of shoulder

Question 9

Teres Minor

Answer 9

O - Lateral border of scapula
I - Inferior facet of greater tubercle of Humerus
N - Axillary nerve (C5, C6)
A - Lateral rotation of shoulder

Question 10

Teres Major

Answer 10

O - Inferior angle of scapula
I - Medial lip of intertubercular sulcus of humerus
N - Lower subscapular nerve (C5-C7)
A - Shoulder extension, adduction, & medial rotation

Question 11

Subscapularis

Answer 11

O - Subscapular fossa of scapula
I - Lesser tubercle of humerus
N - Upper & lower subscapular nerves (C5, C6, C7)
A - Medial rotation of shoulder

Question 12

Pectoralis Major

Answer 12

O - Medial 2/3 clavicle, body of sternum, costal cartilages 2-6
I - Lateral lip of intertubercular sulcus of Humerus
A - Shoulder flexion, adduction, & internal rotation
N - Medial & lateral pectoral nerves

Question 13

Pectoralis Minor

Answer 13

O - Ribs 3-5
I - Coracoid process of scapula
A - Scapula depression, protraction & downward rotation, elevate ribs
N - Medial pectoral nerve

Question 14

Subclavis

Answer 14

O - Rib 1
I - Groove for subclavius on inferior surface of clavicle
A - Shoulder depression & protraction
N - Nerve to subclavius

Question 15

Serratus anterior

Answer 15

O - Ribs 1-8 or 9
I - Medial border of scapula
A - Scapula protraction & upward rotation, elevate ribs
N - Long thoracic nerve

Question 16

Latissimus dorsi

Answer 16

O - T7-L5 spinous processes, ribs 8-12, thoracolumbar fascia
I - Floor of intertubercular sulcus of humerus
A - Shoulder extension, adduction & medial rotation
N - Thoracodorsal nerve

Question 17

Biceps Brachii

Answer 17

O - Short head – coracoid process of scapula,
Long head – supraglenoid tubercle
I - Radial tuberosity
N - Musculocutaneous nerve (lateral cord, C5-C7)
A - Flexion of elbow & shoulder, supination

Question 18

Coracobrachialis

Answer 18

O - Coracoid process
I - Medial humeral diaphysis
N - Musculocutaneous nerve (lateral cord, C5-C7)
A - Shoulder adduction & flexion

Question 19

Triceps Brachii

Answer 19

O - Long head – infraglenoid tubercle of scapula
Lateral head – superior, lateral humeral diaphysis
Medial head – posterior humerus inferior to radial groove
I - Olecranon process of ulna
N - Radial nerve (posterior cord, C5-T1)
A - Extension of elbow & shoulder