Which muscle extends the elbow, with origins from the scapula and posterior humerus, inserting at the olecranon?

Which muscle extends the elbow, with origins from the scapula and posterior humerus, inserting at the olecranon?

• A. Triceps Brachii
• B. Brachialis
• C. Palmaris Longus
• D. Biceps Brachii

Answer: (A)

Elbow extension is carried out by the triceps brachii, a three-headed muscle whose long head originates from the scapula and the other two heads originate from the posterior surface of the humerus. All heads converge to a common tendon that inserts on the olecranon of the ulna, so when the triceps contracts it pulls on the olecranon to straighten the elbow. This matches the description of origins from the scapula and posterior humerus with insertion at the olecranon. The other muscles listed do not extend the elbow: the brachialis flexes the elbow; the biceps brachii flexes the elbow and supinates; the palmaris longus is a weak wrist flexor with a different insertion.

Elbow extension is carried out by the triceps brachii, a three-headed muscle whose long head originates from the scapula and the other two heads originate from the posterior surface of the humerus. All heads converge to a common tendon that inserts on the olecranon of the ulna, so when the triceps contracts it pulls on the olecranon to straighten the elbow. This matches the description of origins from the scapula and posterior humerus with insertion at the olecranon. The other muscles listed do not extend the elbow: the brachialis flexes the elbow; the biceps brachii flexes the elbow and supinates; the palmaris longus is a weak wrist flexor with a different insertion.