Which muscles act as agonists in neck flexion?

• A. Latissimus Dorsi
• B. Biceps Brachii
• C. Trapezius and Levator Scapulae
• D. SCM and Scalenes

Answer: (D)

Neck flexion is produced primarily by the sternocleidomastoid along with the scalene muscles. When both sides contract, the sternocleidomastoid pulls the head forward, bending the neck at the cervical spine. The scalene muscles lie on the side of the neck and assist in flexion (especially in coordination with the SCM) while also helping stabilize the neck and, for the scalenes, aiding in rib elevation during breathing. Because these muscles actively shorten to bring the chin toward the chest, they are the main agonists for neck flexion.

The other muscles listed aren’t primarily neck flexors. Latissimus dorsi and biceps brachii focus on shoulder and elbow movements, not neck flexion. Trapezius and levator scapulae mainly move or stabilize the scapula and can contribute to neck movements in other ways, but they don’t act as the primary neck flexors.