Place the muscle under the appropriate action
Extension of the Shoulder
Flexion of the Shoulder
Latissimus dorsi
Posterior deltoid
Coracobrachialis
Teres major
Anterior deltoid
Pectoralis major
Long head of triceps brachii
Biceps brachii
The Correct Answer and Explanation is :
The muscles involved in shoulder movements can be categorized based on their actions:
Extension of the Shoulder:
- Latissimus Dorsi: This large back muscle is a primary extensor of the shoulder, assisting in moving the arm backward.
- Posterior Deltoid: The rear portion of the deltoid muscle contributes to shoulder extension by pulling the arm backward.
- Teres Major: Located beneath the latissimus dorsi, the teres major assists in extending the arm from a flexed position.
Flexion of the Shoulder:
- Pectoralis Major: This chest muscle is a primary flexor of the shoulder, aiding in moving the arm forward.
- Anterior Deltoid: The front part of the deltoid muscle assists in shoulder flexion by moving the arm forward.
- Coracobrachialis: This muscle helps flex and adduct the arm at the shoulder joint.
- Biceps Brachii: While primarily known for elbow flexion, the biceps brachii also assists in shoulder flexion when the arm is in a supine position.
Understanding these muscle actions is crucial for comprehending shoulder mechanics and for designing effective rehabilitation and training programs targeting specific shoulder movements.