Upper limb
Trapezius, descending part (upper fibers)
Musculus trapezius (pars descendens)
- Origin
- Occipital bone (external occipital protuberance and superior nuchal line) and the nuchal ligament, which connects the spinous processes of C3–C7
- Insertion
- Lateral third of the clavicle
- Function
- Elevates the scapula (shoulder shrug) and assists upward rotation of the glenoid cavity, together with the other two parts and serratus anterior
- Innervation
- Accessory nerve (CN XI) + cervical plexus (C3–C4)
- Movement & chain
- Elevates the scapula; with the scapula fixed, laterally flexes the head to the same side and rotates it to the opposite side. Needed, together with the transverse and ascending parts, to raise the arm above 90°.
- Palpation
- Easily felt between the neck and acromion when shrugging the shoulder ('shrugging the shoulders').
- Clinical
- A common site of myofascial complaints from prolonged screen work (neck tension). Damage to the accessory nerve, for example after neck surgery, causes a drooping shoulder.
- Segmental innervation
- Accessory nerve (XI) motor; proprioception via the cervical plexus C3–C4.
- In clinical practice
- The upper border serves as a landmark for the shoulder line. Not suitable as an injection site: the muscle is too thin and lies too close to the accessory nerve.
- Region in the model
- Upper limb