Anterior Scalene Muscle, Anterior View

Description

Centered in the anterior cervical region, the anterior scalene (musculus scalenus anterior) rises deep to the platysma and sternocleidomastoid, running from the anterior tubercles of the transverse processes of C3 to C6 inferiorly and laterally to the scalene tubercle on the first rib. Medial to it sit the trachea and thyroid region, while laterally the muscle borders the posterior triangle as the sternocleidomastoid tapers toward its clavicular and sternal heads. Superiorly the composition transitions into the suprahyoid and facial musculature, with frontalis, orbicularis oculi, zygomaticus major and minor, buccinator, and orbicularis oris rendered for surface orientation over deeper neck planes. Fiber direction is clear. Anterior scalene anatomy matters because it anchors the interscalene interval, where the subclavian artery and brachial plexus pass posterior to it, while the subclavian vein tracks anterior and inferior to the muscle as it approaches the thoracic inlet. The phrenic nerve typically descends on the anterior surface of anterior scalene, a relationship that explains hemidiaphragmatic paresis after an interscalene brachial plexus block and also guides safer needle trajectories during regional anesthesia. When hypertrophy, spasm, or congenital bands narrow this space, neurogenic thoracic outlet syndrome patterns emerge, often with provocation in neck rotation and arm elevation. Educators can place this plate into head and neck anatomy modules to teach layered dissection logic from facial expression muscles to the deep lateral neck, and to anchor rib one as a landmark for cervical muscle insertions. It also fits anesthesia and pain medicine texts covering interscalene blocks, phrenic nerve risk counseling, and differential diagnosis of thoracic outlet syndromes in women. Anatomical accuracy verified by SciePro's Medical Advisory Board.