Shoulder Anatomy

Question 1

Latissimus Dorsi

Answer 1

Origin: Inferior angle of scapula, spinous processes of last 6 thoracic vertebrae, last 3 or 4 ribs, thoracolumbar aponeurosis and posterior iliac crest

Insertion: Intertubercular groove of the humerus

Action:

• Shoulder extension
• Shoulder adduction
• Shoulder medial rotation

Question 2

Teres Major

Answer 2

Origin: Inferior angle and lower 1/3 of lateral border of scapula

Insertion: Crest of lesser tubercle of the humerus

Action:

• Shoulder extension
• Shoulder adduction
• Shoulder medial rotation

Question 3

Subscapularis

Answer 3

Origin: Subscapular fossa of the scapula

Insertion: Lesser tubercle of the humerus

Action:

• Shoulder medial rotation
• Stabilize head of humerus

Question 4

Infraspinatus

Answer 4

Origin: Infraspinatus fossa of the scapula

Insertion: Greater tubercle of the humerus

Action:

• Shoulder lateral rotation
• Shoulder adduction
• Stabilize head of humerus

Question 5

Supraspinatus

Answer 5

Origin: Supraspinatus fossa of the scapula

Insertion: Greater tubercle of the humerus

Action:

• Shoulder abduction
• Stabilise head of humerus

Question 6

Deltoids

Answer 6

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

Insertion: Deltoid tuberosity

Action:
- Shoulder abduction
Anterior fibres:
- Shoulder flexion
- Shoulder medial rotation
- Shoulder horizontal adduction
Posterior fibres:
- Shoulder extension
- Shoulder lateral rotation
- Shoulder horizontal abduction

Question 7

Pectoralis Major

Answer 7

Origin: Medial 1/2 of clavicle, sternum and cartilage of first 6 ribs

Insertion: Crest of greater tubercle of humerus

Action:

• Shoulder adduction
• Shoulder medial rotation
• Shoulder flexion
• Shoulder horizontal adduction
• Shoulder extension

Question 8

Biceps Brachii

Answer 8

Origin: Short head:
Coracoid process of scapula
Long head:
Supraglenoid tubercle of scapula

Insertion: Tuberosity of the radius and
aponeurosis of biceps brachii

Action:

• Elbow flexion
• Forearm supination
• Shoulder flexion

Question 9

Triceps Brachii

Answer 9

Origin: Long head: infraglenoid tubercle of scapula
Lateral head: Posterior surface of proximal 1/2 of humerus
Medial head: Posterior surface of distal 1/2 of the humerus

Insertion: Olecranon process of the ulna

Action:
- Elbow extension
Long head:
- Shoulder extension
- Shoulder adduction

Question 10

Coracobrachialis

Answer 10

Origin: Coracoid process of scapula

Insertion: Medial surface of mid-humeral shaft

Action:

• Shoulder flexion
• Shoulder adduction