Which statement about the coracobrachialis insertion is true?

Which statement about the coracobrachialis insertion is true?

• A. Medial surface of humerus (just above midpoint)
• B. Radial tuberosity
• C. Coronoid process of ulna
• D. Greater tubercle of humerus

Answer: (A)

The coracobrachialis inserts on the medial surface of the humerus, roughly near the midshaft. This placement lets the muscle flex and adduct the arm at the shoulder by pulling the humerus inward and upward. The other options point to insertions of different muscles: radial tuberosity is where the biceps brachii inserts; the coronoid process of the ulna is where brachialis attaches; and the greater tubercle of the humerus is the attachment site for several rotator cuff muscles. So the medial surface of the humerus is the correct insertion.

The coracobrachialis inserts on the medial surface of the humerus, roughly near the midshaft. This placement lets the muscle flex and adduct the arm at the shoulder by pulling the humerus inward and upward. The other options point to insertions of different muscles: radial tuberosity is where the biceps brachii inserts; the coronoid process of the ulna is where brachialis attaches; and the greater tubercle of the humerus is the attachment site for several rotator cuff muscles. So the medial surface of the humerus is the correct insertion.