The term "pulley bone" refers to a small, oval-shaped bone found in the knee of animals such as chickens and turkeys. This bone is also known by several other names, including the "patella," "kneecap," and "stifle bone." Some veterinarians and animal scientists also refer to this bone as the "oscillator bone," due to its role in helping the leg move smoothly and efficiently. Regardless of what it is called, the pulley bone plays an important role in the overall structure and function of the animal's leg, allowing it to run, jump, and move with ease.