Middle Scalene, Anterior View

Description

Running deep to the sternocleidomastoid, the middle scalene (scalenus medius) occupies the lateral cervical region, arising from the posterior tubercles of the transverse processes of C2 to C7 and descending inferolaterally toward the first rib. From an anterior perspective on a male neck and upper thorax model, its belly sits lateral to the cervical vertebrae and posterior to the anterior scalene, while remaining medial to the shoulder girdle formed by the clavicle and scapula. Superiorly the muscle relates to the base of the skull and mandible in the same field, and inferiorly it approaches the thoracic inlet above the upper ribs. For teaching the root of the neck, this view clarifies the interscalene interval, the muscular corridor between anterior and middle scalene where the trunks of the brachial plexus and the subclavian artery pass. A key landmark. Hypertrophy, spasm, or fibrous bands in or around scalenus medius contribute to neurogenic thoracic outlet syndrome, and surgeons use the scalene triangle as a reference during supraclavicular decompression, first rib resection, and brachial plexus exploration after traction injury. Faculty can drop this image directly into gross anatomy lectures on cervical myology, thoracic inlet anatomy, and brachial plexus organization, or into surgical education materials for thoracic outlet syndrome and regional anesthesia discussions (interscalene block orientation and its relationship to the scalenes). Medical publishers will also find it effective for labeling exercises that contrast sternocleidomastoid with the deeper scalene layer on an anterior neck model. Anatomical accuracy verified by SciePro's Medical Advisory Board.