What are patellae categorized as?

The patellae, commonly known as the kneecaps, are categorized as sesamoid bones. Sesamoid bones are a specific type of bone that forms within tendons and are typically found in areas where a tendon passes over a joint. The primary function of sesamoid bones is to protect tendons from stress and wear and to enhance the mechanical advantage of the muscles acting on the joint.

In the case of the patella, it acts to improve the leverage of the quadriceps muscle, increasing the efficiency of knee extension. This is crucial for activities such as running and jumping, where knee function is heavily relied upon.

Other options refer to different categories of bones. Phalanges are the bones of the fingers and toes, scapulae are the shoulder blades, and metatarsals are the long bones in the foot. None of these categories share the same characteristics or functions as sesamoid bones, highlighting the unique classification of the patellae.