What is the Keller disease?

Keller disease, also known as cervical rib-Thoracic outlet syndrome (TOS), is a rare medical condition involving a bony anomaly caused by an extra rib (called a cervical rib) and narrowing of the outlet at the neck (thoracic outlet), which compresses the blood vessels (subclavian artery) and nerves (brachial plexus), affecting blood flow and nerve function in the arm and hand. Symptoms include pain, cold sensitivity, numbness, muscle weakness, swelling, discoloration, reduced strength, impaired coordination, hand tremors, reduced sensation, fatigue, muscle twitching, tingling sensations, or diminished pulses in the affected arm or hand. It can lead to blood clotting, reduced circulation, decreased sensation, restricted motion, or in severe cases, limb ischemia in the fingers