Question

Explain the anatomical basis for the statement that the left sternocleidomastoid (SCM) muscle contracts to turn the head to the right. How does the contraction of this muscle contribute to the complex movements involved in head rotation, and what other muscles are involved in this process?

Answer 1

The left sternocleidomastoid (SCM) muscle contracts to turn the head to the right due to its anatomical positioning. It works in coordination with other muscles to contribute to the complex movements involved in head rotation.

Step-by-step explanation:

The left sternocleidomastoid (SCM) muscle contracts to turn the head to the right due to its anatomical positioning. Each sternocleidomastoid muscle is attached to the mastoid process of the temporal bone (located behind the ear) and the sternum and clavicle (collarbone). When the left SCM muscle contracts, it pulls the mastoid process towards the left shoulder, causing the head to turn to the right.

The contraction of the left SCM muscle contributes to the complex movements involved in head rotation by working in coordination with other muscles. When the left SCM muscle contracts, it is assisted by the right SCM muscle on the opposite side of the neck, which contracts to stabilize the head and prevent excessive rotation. The muscles in the back of the neck, such as the splenius cervicis, also play a role in head rotation.