Which muscle extends the elbow, and the long head also contributes to extension and adduction of the shoulder?

Which muscle extends the elbow, and the long head also contributes to extension and adduction of the shoulder?

• A. Triceps Brachii
• B. Deltoid
• C. Latissimus Dorsi
• D. Pectoralis Major

Answer: (A)

Elbow extension is carried out mainly by the triceps brachii. All three heads—long, lateral, and medial—pull on the ulna to straighten the elbow. The long head stands out because it crosses the shoulder joint, attaching to the infraglenoid tubercle of the scapula. That anatomical path lets it assist at the shoulder, contributing to shoulder extension and, depending on arm position, adduction as well. The other muscles listed don’t extend the elbow: deltoid mainly moves the shoulder (abduction, flexion, extension via different fibers), latissimus dorsi extends and adducts the shoulder but doesn’t bend the elbow, and pectoralis major mainly flexes, adducts, and medially rotates the shoulder. So the muscle that both extends the elbow and has a long head that can help extend and adduct the shoulder is the triceps brachii.

Elbow extension is carried out mainly by the triceps brachii. All three heads—long, lateral, and medial—pull on the ulna to straighten the elbow. The long head stands out because it crosses the shoulder joint, attaching to the infraglenoid tubercle of the scapula. That anatomical path lets it assist at the shoulder, contributing to shoulder extension and, depending on arm position, adduction as well. The other muscles listed don’t extend the elbow: deltoid mainly moves the shoulder (abduction, flexion, extension via different fibers), latissimus dorsi extends and adducts the shoulder but doesn’t bend the elbow, and pectoralis major mainly flexes, adducts, and medially rotates the shoulder. So the muscle that both extends the elbow and has a long head that can help extend and adduct the shoulder is the triceps brachii.