Muscles / Back
Trapezius
- Back
- Shoulder & scapula
- Superficial layer
Anatomy
- Origin
- Medial third of the superior nuchal line, external occipital protuberance, ligamentum nuchae, spinous processes of C7-T12
- Insertion
- Lateral third of the clavicle, acromion and spine of the scapula
- Nerve
- Spinal accessory nerve (CN XI), motor; C3-C4 (pain and proprioception) (CN XI; C3-C4 sensory)
Actions
- Upper part elevates the scapula
- Middle part retracts the scapula
- Lower part depresses the scapula
- Upper and lower parts together upwardly rotate the scapula
Parts
Notes
- Spinal accessory nerve injury (e.g. after posterior triangle surgery) causes shoulder droop and lateral scapular winging.
- Upper/lower trapezius imbalance is a common rehabilitation target in shoulder pain.
References (5)
- Cools AM, Dewitte V, Lanszweert F, et al. Am J Sports Med. 2007;35(10):1744-1751. Rehabilitation of scapular muscle balance: which exercises to prescribe?
- Standring S, ed. Elsevier. Gray's Anatomy: The Anatomical Basis of Clinical Practice. 42nd ed.
- Dalley AF, Agur AMR. Wolters Kluwer. Moore's Clinically Oriented Anatomy. 9th ed.
- Neumann DA. Elsevier. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. 3rd ed.
- Betts JG, Young KA, Wise JA, et al. OpenStax (free, openly licensed textbook). Anatomy and Physiology 2e