Posterior Scalene, Lateral View

Description

Running obliquely along the lateral neck, the posterior scalene is shown deep to the sternocleidomastoid and posterior to the middle scalene, extending from the posterior tubercles of the transverse processes of the mid to lower cervical vertebrae (classically C4 to C6) to its insertion on the external surface of the second rib. Superiorly it sits just inferior to the skull base and atlas-axis complex, while inferiorly it approaches the thoracic inlet near the first and second costal attachments. The lateral perspective keeps the cervical vertebral column, upper thoracic vertebrae, ribs, clavicle, and scapula in clear relationship to the muscle’s fiber direction. Landmarks read cleanly. For teaching the scalene triangle, this lateral cut is practical because it lets you map where the brachial plexus trunks and subclavian artery pass between the anterior and middle scalene, while the subclavian vein stays anterior to the anterior scalene. Posterior scalene hypertrophy or spasm can contribute to thoracic outlet syndrome presentations, and it also becomes a reference when explaining second-rib elevation mechanics in accessory inspiration. A small muscle. A frequent source of confusion. Use this artwork in gross anatomy and musculoskeletal anatomy courses to contrast the scalene group with levator scapulae and sternocleidomastoid, or in anesthesia education when orienting learners for interscalene and supraclavicular block anatomy and common complications such as pneumothorax risk near the apical pleura. It also suits surgical and radiology publications discussing thoracic outlet decompression and cervical rib variants. Anatomical accuracy verified by SciePro's Medical Advisory Board.