What is the primary function of the sternocleidomastoid muscle?

What is the primary function of the sternocleidomastoid muscle?

• A. Connects the scapulae together
• B. Allows flexion of the neck
• C. Allows movement of the head
• D. Provides respiration

Answer: (C)

The primary function of the sternocleidomastoid muscle is to allow movement of the head. This large muscle runs from the sternum and clavicle up to the mastoid process of the skull, enabling the rotation and lateral flexion of the head. When one side of the muscle contracts, it turns the head to the opposite side; when both sides contract together, they help flex the neck forward. This muscle plays a crucial role in head positioning and movements, which are essential for various activities such as looking around and maintaining posture. The other options highlight muscles and functions not directly associated with the sternocleidomastoid. While the muscle can contribute to neck flexion, its primary function is more related to head movement, making the option focused on movement the most accurate representation of the muscle's role.

The primary function of the sternocleidomastoid muscle is to allow movement of the head. This large muscle runs from the sternum and clavicle up to the mastoid process of the skull, enabling the rotation and lateral flexion of the head. When one side of the muscle contracts, it turns the head to the opposite side; when both sides contract together, they help flex the neck forward. This muscle plays a crucial role in head positioning and movements, which are essential for various activities such as looking around and maintaining posture.

The other options highlight muscles and functions not directly associated with the sternocleidomastoid. While the muscle can contribute to neck flexion, its primary function is more related to head movement, making the option focused on movement the most accurate representation of the muscle's role.