Middle Scalene, Posterior View

Description

Posteriorly, the middle scalene (scalenus medius) is exposed as a tall, straplike muscle occupying the lateral cervical region, deep to trapezius and levator scapulae and posterolateral to the cervical vertebral column. Its proximal attachments arise from the posterior tubercles of the transverse processes of C2 to C7, forming a stepped series of muscular slips that descend inferolaterally toward the thoracic inlet. Laterally, the muscle belly approaches the supraclavicular fossa and the first rib, with the interscalene interval lying anterior to it where the anterior scalene would normally form the other boundary. Clear fiber direction. Clean bony landmarks. This posterior perspective matters when you are teaching or planning exposure of the scalene triangle and cervicothoracic junction, because the middle scalene is both a landmark and a potential site of neurovascular conflict. Hypertrophy or spasm can contribute to neurogenic thoracic outlet syndrome by narrowing the interscalene space around the brachial plexus trunks, and botulinum toxin injection or surgical scalenectomy requires confident orientation to its cervical transverse process attachments and relation to the first rib. The muscle’s position also helps explain why lateral neck pain can refer toward the shoulder girdle during scalene strain. Use this asset for gross anatomy lab manuals, spine and peripheral nerve teaching decks, and operative anatomy figures discussing thoracic outlet decompression, supraclavicular approaches, or regional anesthesia planning near the interscalene groove. It also suits radiology adjuncts when correlating surface anatomy with axial imaging at the cervical root level. Anatomical accuracy verified by SciePro's Medical Advisory Board.