Terminology - Interior
The leg channel is the portion of the pad where the goaltender's leg makes contact with the pad.
The knee protector is a protector attached to the pad which is designed to protect the knee from shots. This is usually limited to the top of the knee and part of the thigh.
Newer style knee protectors wrap around the knee as thigh boards were banned in the NHL a few years ago. Some pad manufacturers will however give the option of adding thigh boards to the pads. An image of thigh boards is displayed below.
The knee wrap ensures the pad remains in good contact with the knee. It usually also has some additional padding to protect the sides of the knee from impacts with pucks or to help cusion the butterfly.
The calf wrap ensure the leg has good contact with the leg section of the pad. It also has some additional padding to protect from shots.