* Femur (thigh bone): The largest bone in the horse's leg, it connects to the stifle joint (like our knee) above and the knee joint below.
* Tibia (shin bone): Connects to the femur above and the cannon bone below.
* Fibula (small bone): Located on the outside of the tibia and fuses to it in adult horses.
* Patella (kneecap): A small, round bone that sits in front of the femur and helps with extension of the knee.
* Sesamoid bones (small bones): There are two small sesamoid bones embedded in the tendons on the back of the knee.
So, technically, the horse's knee has a complex combination of bones, not a single number.