Final answer:
The patella is classified as a sesamoid bone, which is a small, round bone that forms in tendons subjected to high mechanical stress to protect tendons and aid in joint movement.
Step-by-step explanation:
The type of bone that the patella is classified as, according to its shape, is a sesamoid bone. Sesamoid bones are small, round bones that form in tendons where there is a great deal of pressure generated in a joint. They function to protect tendons from compressive forces and to improve the mechanical function of the joints.
The patella, or kneecap, is the most common example of a sesamoid bone, as it is found in all humans. It protects the patellar tendon and also provides leverage for the muscles of the thigh to extend the leg. Different from short bones, which have a length nearly equal to their width, sesamoid bones like the patella are typically embedded within a tendon.