Fracture-dislocation of the humeral head into the thoracic cavity is a rare injury. We present one such case in a 70-year-old woman. She presented with a 4-part fracture-dislocation of the proximal humerus, with displacement of the humeral head into the thoracic cavity. She had no signs of acute distress or hemodynamic instability. She underwent hemiarthroplasty of the right shoulder, but the humeral head fragment could not be removed. At 27-month follow-up, the patient had limited mobility of her right shoulder due to axillary nerve palsy but no pain or intrathoracic complications. In the absence of intrathoracic complications, the removal of the humeral head may not be necessary.