Upper limb
Trapezius, ascending part (lower fibers)
Musculus trapezius (pars ascendens)
- Origin
- Spinous processes of Th5–Th12
- Insertion
- Tubercle of the scapular spine (medial end)
- Function
- Depresses the scapula (pulling the shoulder blade downward) and assists upward rotation of the glenoid cavity
- Innervation
- Accessory nerve (CN XI) + cervical plexus (C3–C4)
- Movement & chain
- Depresses the scapula; works together with the descending and transverse parts in upwardly rotating the glenoid cavity during arm elevation above 90°.
- Palpation
- Follow the spinous processes of the lower thoracic vertebrae obliquely upward to the medial border of the scapular spine.
- Clinical
- Can become weakened after a prolonged slumped (kyphotic) posture, which impairs upward scapular rotation.
- Segmental innervation
- Accessory nerve (XI) motor; proprioception via the cervical plexus C3–C4.
- In clinical practice
- Safe transfer techniques avoiding arm traction (prevents shoulder subluxation in stroke patients); monitor injection sites and offload scapular pressure.
- Region in the model
- Upper limb