The trapezius muscle is one of the superficial muscles of the back. The superficial group of back muscles attach the axial skeleton to the upper part of the appendicular skeleton, and may also be referred to as the appendicular group of back muscles.
The superficial group of back muscles includes the following muscles:
- Trapezius
- Latissimus dorsi
- Rhomboid major
- Rhomboid minor
- Levator scapulae
Origin
- Superior nuchal line
- External occipital protuberance
- Ligamentum nuchae
- Spinous processes of C7-T12
Insertion
- Lateral 1/3 of clavicle
- Acromion
- Spine of scapula
Action
- Upper fibres: Elevation of scapula and rotation of scapula during humerus abduction
- Middle fibres: Retract the scapula
- Lower fibres: Depress the scapula
- Acting bilaterally: extension of the neck
Innervation
- Motor: accessory nerve (XI)
- Proprioception: C3,4
Blood Supply
Transverse cervical artery