Anterior Scalene Muscle Beneath the Skin, Anterior View

Description

Beginning at the transverse processes of the midcervical vertebrae, the anterior scalene (scalenus anterior) descends anterolaterally to its insertion on the scalene tubercle of the first rib, positioned deep to the sternocleidomastoid and lateral to the visceral midline of the neck. Medial to its belly lie the carotid sheath structures in expected relation, while the muscle forms a muscular boundary that separates the anterior neck compartment from the lateral cervical region. Laterally and slightly posterior, the middle scalene (scalenus medius) is implied as the next layer, with the brachial plexus roots and subclavian artery typically coursing between the two muscles. Depth matters here. Clinically, this anterior perspective clarifies why the anterior scalene is a high-stakes landmark for procedures at the root of the neck: the phrenic nerve usually runs on its anterior surface, and a deep needle trajectory can drift toward the subclavian vessels or pleura at the thoracic inlet. Hypertrophy or spasm of the scalene group is a common contributor to neurogenic thoracic outlet syndrome, where symptoms follow lower brachial plexus distribution and worsen with overhead activity. The relationship of the anterior scalene to the first rib also frames the mechanics of scalene muscle release and first-rib resection in selected refractory cases. Neck anatomy teaching benefits from this layering, from gross anatomy dissection guides to surgical anatomy chapters that explain the interscalene triangle, supraclavicular approaches, and safe planes for regional anesthesia such as interscalene block. Medical publishers can pair it with cross-sectional imaging or surface landmarks to orient learners from superficial sternocleidomastoid and trapezius to deeper scalenes, vessels, and nerves in a male adult model. Anatomical accuracy verified by SciePro's Medical Advisory Board.