Question

Does the highlighted muscle flex the neck to the same side or to the opposite side

Answer 1

I found the exercise on the internet and attached is the image with the highlighted muscle.
The highlighted muscle is the anterior scalene, it belongs to the scalene group and is positioned deep behind the sternocleidomastoid muscle. This muscle, anterior scalene, as well as the middle scalene, laterally flex the neck to the same side at the same time that elevates the first rib.