Trapezius Muscle Structure

Description

Spanning the posterior neck and upper thorax, the trapezius is rendered as a broad superficial sheet with a superior portion ascending to the occipital region and nuchal ligament, a middle portion running transversely toward the acromion and spine of the scapula, and an inferior portion descending toward the lower thoracic spinous processes. Lateral fibers converge on the clavicle and scapular spine, lying superficial to the levator scapulae and rhomboid major and minor along the medial border of the scapula. Inferiorly, the latissimus dorsi covers the lower back, while the infraspinatus and teres minor and major occupy the posterior scapula, all oriented around the glenohumeral and scapulothoracic region. Posterior viewing is the clearest way to teach scapular mechanics because the trapezius coordinates with serratus anterior to produce upward rotation during arm elevation, and imbalance is visible as scapular dyskinesis, shoulder shrug asymmetry, or a winged medial border. Neck and shoulder pain clinics often localize myofascial trigger points to the upper trapezius near the superior angle of the scapula, and selective denervation or botulinum toxin injection planning depends on reliable surface and deep landmarks. Accessory nerve (CN XI) injury after posterior triangle lymph node biopsy or neck dissection produces trapezius atrophy and lateral scapular droop. It is a classic complication. Use this artwork for gross anatomy and kinesiology instruction on the posterior thorax, for orthopaedic and sports medicine materials on scapulothoracic rhythm, and for physiotherapy guides addressing upper crossed syndrome and trapezius re-education after whiplash. Anatomical accuracy verified by SciePro's Medical Advisory Board.