Which muscles act as agonists in right lateral flexion of the neck?

• A. Right SCM, Right Scalenes, Right Trapezius, Right Levator Scapulae
• B. Left SCM, Left Scalenes, Left Trapezius, Left Levator Scapulae
• C. Pectoralis Major
• D. Latissimus Dorsi

Answer: (A)

To bend the neck to the right, the muscles on the right side contract to pull the head toward that same side. The right sternocleidomastoid acts unilaterally to tilt the head to the right (and also helps rotate the face to the left), making it a primary contributor. The right scalenes similarly assist in lateral flexion to the right and support the motion. The right trapezius and right levator scapulae can also help with this bending when the neck or shoulder girdle is stabilized, adding to the effort from the SCM and scalenes. Together, these right-sided muscles provide the main force for right lateral neck flexion, while the left-side muscles would oppose this movement, and the chest and back muscles listed in other options don’t primarily drive neck lateral bending.