Patella

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For other uses, see Patella (disambiguation).
Bone: Patella
Left patella - anterior aspect
Left patella - posterior aspect
Gray's subject #60 255
MeSH A02.835.232.043.650.624

The patella or kneecap is a thick, triangular bone which articulates with the femur and covers and protects the front of the knee joint. It is the largest sesamoid bone in the human body. It is attached to the tendon of the quadriceps femoris muscle, which contracts to straighten the leg. The vastus intermedialis muscle is attached to the base of patella. The vastus lateralis and vastus medialis are attached to lateral and medial borders of patella respectively.

The primary functional role of the patella is knee extension. The patella increases the leverage that the tendon can exert on the femur by increasing the angle at which it acts.

The patella ossifies between the ages 2-6 years. In some people it may be absent congenitally or hypoplastic. In 2% of the population there is a bipartite patella, which is usually asymptomatic.


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Human Bones
v  d  e
VERTEBRAL COLUMN: vertebrae (cervical - atlas - axis | thoracic | lumbar) | sacrum | coccyx

THORAX: sternum | rib

cranial bones of SKULL: occipital | parietal | frontal | temporal | sphenoid | ethmoid

facial bones of SKULL nasal | maxilla | lacrimal | zygomatic | palatine | inferior nasal conchae | vomer | mandible | hyoid

UPPER EXTREMITY: clavicle | scapula | humerus | ulna | radius

carpals (scaphoid | lunate bone | triquetral | pisiform | trapezium | trapezoid | capitate | hamate) | metacarpals | phalanges (prox | int | dist)

LOWER EXTREMITY: pelvis (ilium, ischium, pubis) | femur | patella | fibula | tibia

tarsals (calcaneus | talus | navicular | cuneiform | cuboid ) | metatarsals | phalanges (prox | int | dist)

OSSICLES: malleus | incus | stapes