Wrist tendonitis, also called tenosynovitis, is a common condition characterized by irritation and inflammation of the tendons around the wrist joint. Tendonitis occurs at points where the tendons of the wrist cross each other or pass over a bony prominence.Tendons are tough, flexible, fibrous bands of tissue that connect muscles to bones. They can be small, like the delicate, tiny bands in the hands, or large, like the heavy, rope-like cords that anchor the calf or thigh muscles. When tendons become inflamed, irritated or suffer microscopic tears, the condition is called Tendonitis.