Currently, increasing participation in sports has contributed to an increase in sports injuries for both amateurs and professionals. The anatomy of the flexor and extensor tendon systems of the hand is very complex. Each component of these systems may be impaired due to sports injuries, even leading to permanent disability. Therefore, it is essential to understand the complex anatomy of the hand in the diagnosis and treatment of tendon injuries. In this article, a definition was made on the basis of anatomical structures of tendon injuries in athletes.