In all flexion actiities, symmetrical or asymmetrical sternocleidomastoids were the major flexor muscles, and they had to balance the mechanics of the neck as agonists, synergists, or antagonists.

• 在所有的前屈肌中，对称性的和不对称的胸锁乳突肌是主要的前屈肌，并且，他们在颈椎的运动中，承担着主动肌、平衡肌和拮抗肌的作用。