Patella

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Bone: Patella
Knee diagram
Gray's subject #60 255
MeSH Patella

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 patella is stabilised by the insertion of vastus medialis and the prominence of the anterior femoral condyles, which prevent lateral dislocation during flexion. The retinacular fibres of the patella also stabilise it during exercise.

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.

Regarding non-human animals, the patella is fully developed only in placental mammals; marsupials have only rudimentary, non-ossified patellae.[1]

Contents

Lower extremity

Left patella - anterior aspect

Left patella - posterior aspect

Right knee-joint. Anterior view.

Sagittal section of right knee-joint.

Capsule of right knee-joint (distended). Lateral aspect.

Front and medial aspect of right thigh.

Lateral aspect of right leg.

  1. ^ Herzmark MH (1938). "The Evolution of the Knee Joint". J Bone Joint Surg Am 20: 77-84. Retrieved on 2007-11-17. 

v • d • e
Bones of lower limbs
Femur head of femur (fovea capitis femoris) - neck of femur - greater trochanter - trochanteric fossa - lesser trochanter - tubercle of the femur - intertrochanteric line - intertrochanteric crest - linea quadrata

body (linea aspera, third trochanter, pectineal line, adductor tubercle)

lower extremity (lateral condyle, medial condyle, lateral epicondyle, medial epicondyle, patellar surface)
Tibia upper extremity: medial condyle - lateral condyle - intercondyloid eminence - tuberosity of the tibia - posterior intercondyloid fossa - anterior intercondyloid fossa

body: soleal line

lower extremity: medial malleolus
Fibula head of fibula - body of fibula - lateral malleolus
Tarsus calcaneus (sustentaculum tali, trochlear process) - talus - navicular - cuboid - cuneiform (medial, intermediate, lateral)
Metatarsus 1st metatarsal - 2nd - 3rd - 4th - 5th
Other patella - phalanges of the foot
 This musculoskeletal system article is a stub. You can help Wikipedia by expanding it.
Retrieved from "http://en.wikipedia.org/wiki/Patella"
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