The superior trunk block (STB) is a refinement of the interscalene block, providing effective analgesia for shoulder surgery while reducing the risk of phrenic nerve palsy. It targets the superior trunk of the brachial plexus (C5–C6) as it courses between the anterior and middle scalene muscles, before giving rise to the suprascapular and lateral pectoral nerves. Compared to the interscalene block, STB offers reduced hemidiaphragmatic paralysis while maintaining adequate shoulder analgesia. Ultrasound guidance ensures accurate needle placement and local anaesthetic spread, minimizing complications such as vascular puncture, pneumothorax, or Horner’s syndrome.