Trapezius
From WikiMSK
| Trapezius | |
|---|---|
| Muscle Type | |
| Origin | The upper fibers originate from the medial third of the superior nuchal line and the external occipital protuberance, the middle fibers from the nuchal ligament and spinous processes of C7-T3, and the lower fibers from the spinous processes of T4-T12. |
| Insertion | The upper fibers insert on the lateral third of the clavicle, the middle fibers on the acromion and superior crest of the spine of the scapula, and the lower fibers on the medial end of the spine of the scapula. |
| Action | The upper fibers elevate and upwardly rotate the scapula, the middle fibers retract the scapula, and the lower fibers depress and upwardly rotate the scapula. |
| Synergists | |
| Antagonists | |
| Spinal innervation | Cranial nerve XI (motor), C3 and C4 ventral rami (sensory and proprioception) |
| Peripheral Innervation | |
| Vasculature | transverse cervical artery, with contributions from the dorsal scapular artery and posterior intercostal arteries. |
The shoulder shrug test is poor for testing trapezius function. Test instead arm abduction over the head.
