Posterior Scalene, Anterior View

Description

Arising from the posterior tubercles of the lower cervical transverse processes, the posterior scalene (scalenus posterior) descends obliquely inferolaterally to its insertion on the external surface of the second rib, positioned posterior to the scalenus medius and deep to the sternocleidomastoid in an anterior view. The cervical vertebrae, first and second ribs, and clavicles provide the bony framework, with the posterior scalene running lateral to the vertebral column and superior to the upper rib cage. Expect the muscle belly to appear as a slender band at the lateral neck, just posterior to the larger middle scalene. Bony landmarks anchor the read. An anterior perspective on a posterior neck muscle sounds counterintuitive, but it is exactly what you need when teaching layered dissection and when orienting trainees to the scalene interval at the root of the neck. The posterior scalene is often spared in classic anterior scalene syndrome, yet its relationship to the first two ribs and to scalenus medius matters during supraclavicular approaches, interscalene regional anesthesia planning, and workups where a cervical rib or fibrous band alters the mechanics of the thoracic outlet. Its second rib insertion also ties it to upper rib elevation patterns seen with accessory respiratory recruitment in COPD and in some neck pain presentations. Use this asset for gross anatomy lab manuals, physical therapy and chiropractic coursework on lateral cervical musculature, and surgical education materials that clarify scalene layering relative to the clavicle, first rib, and brachial plexus region. It also fits radiology teaching that correlates neck muscle planes with CT or MRI anatomy at the lower cervical levels. Anatomical accuracy verified by SciePro's Medical Advisory Board.