Upper limb
Acromioclavicular ligament
Ligamentum acromioclaviculare
- Origin
- Lateral extremity of the clavicle
- Insertion
- Superior aspect of the acromion process of the scapula
- Function
- Reinforces the superior AC joint capsule, providing primary horizontal stability against anteroposterior translation
- Innervation
- Suprascapular nerve and axillary nerve
- Movement & chain
- Permits scapular rotation and tilt during humeral elevation
- Palpation
- Palpable directly on top of the shoulder at the AC joint line
- Clinical
- AC joint separation (Rockwood types I–VI) from direct fall onto shoulder ('piano key' sign); AC joint osteoarthritis.
- Segmental innervation
- C5–C6
- In clinical practice
- Scarf test / cross-body adduction test, taping, and scapulothoracic strengthening
- Region in the model
- Upper limb