Anterior scalene (scalenus anterior)

The anterior scalene (scalenus anterior) is the first muscle of the scalene muscle group. It is a deep muscle that lies on the lateral part of the neck behind the sternocleidomastoid. The thickness of the anterior scalene varies, and it is thicker at the level of the cricoid cartilage of the larynx while thinner at the level of its insertion and origin sites. 

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