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The patella (), also known as the kneecap or kneepan, is a thick, circular-triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint. The patella is found in most vertebrates such as mice, cats, and birds, but not in whales or most reptiles and amphibians such as snakes or frogs. In humans, the patella is the largest sesamoid bone in the body. Babies are born with a patella of soft cartilage which begins to ossify into bone at about three years of age. == Structure == The patella is a sesamoid bone roughly triangular in shape, with the apex of the patella facing downards.The apex is the most inferior (lowest) part of the patella. It is pointed in shape, and gives attachment to the patellar ligament. The front and back surfaces are joined by a thin margin and towards centre by a thicker margin. The tendon of the quadriceps femoris muscle attaches to the base of the patella.,〔 with the vastus intermedius muscle attaching to the base itself, and the vastus lateralis and vastus medialis are attached to outer lateral and medial borders of patella respectively. The upper third of the front of the patella is coarse, flattened, and rough, and serves for the attachment of the tendon of the quadriceps and often has exostoses. The middle third has numerous vascular canaliculi. The lower third culminates in the apex which serves as the origin of the patellar ligament.〔 The posterior surface is divided into two parts.〔 Patella ant.jpg|Human left patella from the front Patella post.jpg|Human left patella from behind The upper three-quarters of the patella articulates with the femur and is subdivided into a medial and a lateral facet by a vertical ledge which varies in shape. In the adult the articular surface is about and covered by cartilage, which can reach a maximal thickness of in the centre at about 30 years of age. The lower part of the posterior surface has vascular canaliculi filled and is filled by fatty tissue, the infrapatellar fat pad. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「patella」の詳細全文を読む スポンサード リンク
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