Middle Scalene Muscle, Anterior View

Description

Running deep to the sternocleidomastoid in an anterior neck view, the middle scalene (musculus scalenus medius) occupies the central column of the scalene group, lateral to the cervical vertebrae and medial to the more posterolateral levator scapulae. Its fibers descend inferolaterally from the posterior tubercles of the cervical transverse processes (classically C2 to C7) to a broad insertion on the superior surface of the first rib, posterior to the subclavian groove. Anterior scalene lies anteromedial, while posterior scalene sits posterior, framing the interscalene space. Key landmarks remain readable. That relationship matters because the brachial plexus roots and trunks pass between anterior and middle scalene, and the subclavian artery tracks with them, making this muscular interval the anatomic bottleneck in neurogenic and arterial thoracic outlet syndrome. When the middle scalene hypertrophies or spasms after whiplash or repetitive overhead activity, traction and compression symptoms tend to localize along C5 to T1 distributions, and palpation or provocative maneuvers often reproduce paresthesia. An anterior perspective also supports teaching for interscalene brachial plexus block planning, where the needle target lies lateral to the carotid sheath and posterior to the anterior scalene, with the middle scalene forming the posterior boundary. Faculty can place this artwork directly into gross anatomy and head and neck courses to explain scalene attachments, fascial compartments, and the logic behind the interscalene triangle. It also suits anesthesia and pain medicine slide decks on scalene blocks, as well as clinical anatomy chapters discussing thoracic outlet syndrome and cervical rib variants in women. Anatomical accuracy verified by SciePro's Medical Advisory Board.