Der Musculus trapezius (latin for "muscle“; trapezius "trapezoidal form“) or simply called the "traps" is a muscle covering both sides of the upper spine, extending from the posterior extremities to the lower thoracic vertebrae and laterally upwards to the scapulae.

Shoulder blade

M. Trapezius

Origin
Protuberantia occipitalis externa, intervertebral discs, spinal processes of the cervical and thoracic spine
Attachments
Collarbone (clavicula), shoulder blade (acromion and apina scapulae)
Function
Movement of the shoulder blades
Innervation
Nervus accessorius branches to the plexus cervicalis
Spinal Segment
C2-C4