In neck flexion, which muscles act as antagonists?

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

Answer: (A)

When you flex the neck, the chin moves toward the chest because the neck flexors—primarily the sternocleidomastoid and the anterior scalene group (along with deep neck flexors)—are shortening to pull the head forward. The muscles that oppose this forward motion are the neck extensors. The upper trapezius and the levator scapulae, especially when the shoulder girdle is stabilized, act to extend the cervical spine or resist forward bending, making them good antagonists to neck flexion. The trapezius in particular helps pull the head back, while the levator scapulae can contribute to extension of the neck when the scapula isn’t moving.

The other muscles listed don’t primarily oppose neck flexion. The sternocleidomastoid and scalene muscles are actually neck flexors, so they don’t act as antagonists. Latissimus dorsi and deltoid are shoulder muscles with actions centered on the arm and shoulder joint, not the neck, so they don’t counteract neck flexion in this context.