Abstract
Twelfth rib syndrome is a rare condition that causes severe pain in the loin. The diagnosis of this phenomenon is based on the patient's medical history and physical examination findings. However, many clinicians still lack an understanding of the disease; this delays an accurate diagnosis, causing patients to experience prolonged pain without proper treatment. We herein describe a 72-year-old woman and a 47-year-old woman with loin pain. They had undergone various imaging tests, but the cause of the pain remained unknown. Their pain was reproduced by the hooking maneuver, and twelfth rib syndrome was diagnosed. Both patients were immediately relieved of pain after a twelfth intercostal nerve block. Early diagnosis and appropriate treatment are needed for pain relief in patients with twelfth rib syndrome.