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Trapezius Muscle
Definition Trapezius is a muscle of the shoulder and upper limb
Origin : External occipital protuberance
Superior nuchal line of the occipital bone
Ligamentum nuchae
Spinous processes of C7 and all Thoracic vertebrae
Insertion : Lateral third of the clavicle
Medial margin of the acromion,
Posterior border of the spine of the scapula.
Innervation : Motor : Accessory nerve
Sensory : C3,4
Actions and exercises : Contraction causes : movement of the scapulae when the spinal origins are stable, and movement of the spine when the scapulae are stable.
The upper portion of the trapezius can be developed by elevating the shoulders
Middle fibers are developed by pulling shoulder blades together.
The lower part can be developed by drawing the shoulder blades downward while keeping the arms almost straight and stiff.
