Location of the Anterior Scalene Muscle

Description

Anterior scalene muscle is rendered on the anterolateral cervical region of an adult female, descending from the anterior tubercles of the transverse processes (C3 to C6) to insert on the scalene tubercle of the first rib. Laterally, the muscle forms the anterior boundary of the interscalene interval, where the roots and trunks of the brachial plexus and the subclavian artery course posterior to it, while the subclavian vein remains anterior and inferior, separated by the clavicle and first rib. Medially, the anterior scalene sits deep to the sternocleidomastoid and platysma and abuts the prevertebral fascia; the phrenic nerve tracks obliquely on its anterior surface toward the thorax. Superior facial musculature (orbicularis oculi, orbicularis oris, temporalis) and the upper torso musculature (pectoralis major, deltoid) provide surface context, with a breast cross-section demonstrating glandular lobules, ducts, and surrounding adipose tissue. Anesthesiologists and surgeons care about this topology because the anterior scalene is the key landmark for an interscalene brachial plexus block and for understanding predictable complications such as ipsilateral hemidiaphragmatic paresis from phrenic nerve involvement. Thoracic outlet syndrome also concentrates here: scalene hypertrophy, fibrous bands, or postural narrowing can compress the neurovascular bundle in the interscalene triangle, producing paresthesias and exertional arm pain. Small distances matter. Confusing the subclavian artery with the anteriorly placed subclavian vein has consequences during supraclavicular procedures. Useful placements include teaching head and neck myology in gross anatomy and physical therapy curricula, illustrating cervical regional anesthesia in an anesthesia atlas, and supporting chapters on thoracic outlet syndrome, brachial plexopathy, and neck dissection approaches in surgical texts. It also suits patient education materials that need the neck-to-chest continuity, including female breast anatomy context, without sacrificing cervical detail. Anatomical accuracy verified by SciePro's Medical Advisory Board.