The patella is classified as a sesamoid bone, which is a small irregularly shaped bone, and it is embedded in a tendon or a muscle. The Kneecap, known as the patella, is the largest sesamoid bone in the human body; it is rooted within tendons, and their general purpose would be to protect a joint and the tendon.
There are also sesamoid bones located at the first metatarsal, or the big toe, the vertebrae, sacrum, hand, and mandible. Out of the 206 bones that are in the body, there may be a small percentage of sesamoid bones; however, they are an essential part of the skeletal system.