Patela - Patella
The patella (knee cap) is a flat, triangular bone, situated on the front of the knee-joint. It is usually regarded as a sesamoid bone, developed in the tendon of the Quadriceps femoris, and resembles these bones (1) in being developed in a tendon; (2) in its center of ossification presenting a knotty or tuberculated outline; (3) in being composed mainly of dense cancellous tissue. It serves to protect the front of the joint, and increases the leverage of the Quadriceps femoris by making it act at a greater angle. It has an anterior and a posterior surface three borders, and an apex.
This definition incorporates text from a public domain edition of Gray's Anatomy (20th U.S. edition of Gray's Anatomy of the Human Body, published in 1918 – from http://www.bartleby.com/107/).
Anatomia geral > Ossos; sistema esquelético > Esqueleto apendicular > Ossos do membro inferior > Parte livre do membre inferior > Patela