Posterior Scalene Muscle

Description

Lateral cervical anatomy is rendered with emphasis on the posterior scalene muscle on the right side of an adult male, positioned deep to the sternocleidomastoid and posterior to the anterior and middle scalenes. Its muscle belly arises from the posterior tubercles of the transverse processes of the lower cervical vertebrae and courses inferiorly to insert on the external surface of the second rib, placing it posterior and slightly lateral to the brachial plexus as it descends toward the thoracic inlet. Adjacent landmarks include the cervical vertebral column, the thoracic cage, and the scapula, with the levator scapulae running posterolaterally from the upper cervical transverse processes to the superior angle of the scapula. Bone context includes the skull base, clavicle, scapula, and proximal humerus. This relationship matters at the root of the neck, where scalene anatomy frames common compression sites for neurovascular structures. Hypertrophy or spasm of the scalenes can contribute to thoracic outlet syndrome, but posterior scalene involvement is often overlooked compared with anterior scalene tightness; this view helps you appreciate its rib attachment and its proximity to the interscalene space and supraclavicular fossa. The insertion on rib 2 also makes it a useful teaching contrast with anterior and middle scalenes, which attach to rib 1, and it clarifies why scalene blocks and supraclavicular approaches require careful spatial reasoning around the brachial plexus and subclavian vessels. Small muscle, big consequences. Use this artwork in gross anatomy and kinesiology modules on cervical respiration and lateral flexion, in anesthesia education for regional techniques at the neck, or in surgical and rehabilitation texts discussing thoracic outlet syndrome and neck pain patterns. It also fits well in radiology teaching when correlating surface anatomy with CT or ultrasound landmarks at the thoracic inlet. Anatomical accuracy verified by SciePro's Medical Advisory Board.