| Bone: Patella | |
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| 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 knee joint. Introduction ( classes Long bones body or Diaphysis Medullary canal Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books Bones are rigid organs that form part of the Endoskeleton of Vertebrates They function to move support and protect the various organs of the body produce The femur is the thigh bone In Humans, it is the longest, most voluminous and strongest Bone. It is the largest sesamoid bone in the human body. In Anatomy, a sesamoid bone is a Bone embedded within a Tendon. It is attached to the tendon of the quadriceps femoris muscle, which contracts to extend/straighten the knee. A tendon (or sinew) is a tough band of Fibrous connective tissue that usually connects Muscle to Bone and is capable of withstanding tension "Quads" redirects here For other uses see Quad The quadriceps femoris ( Latin for "four-headed of the femur" also The knee is the lower extremity Joint connecting the Femur, Patella, and the Tibia. The vastus intermedialis muscle is attached to the base of patella. The Vastus intermedius (Crureus arises from the front and lateral surfaces of the body of the femur in its upper two-thirds and from the lower part of the lateral intermuscular septum The vastus lateralis and vastus medialis are attached to lateral and medial borders of patella respectively. The Vastus lateralis (Vastus externus is the largest part of the Quadriceps femoris. The vastus medialis, often called the 'teardrop' muscle is a Medially located Muscle of the Quadriceps.
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 vastus medialis, often called the 'teardrop' muscle is a Medially located Muscle of the Quadriceps. 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. Ossification is the process of Bone formation in which connective tissues such as Cartilage are turned to bone or bone-like tissue 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. See also Evolution of mammals Eutheria ("true beast" are a group of Mammals consisting of Placental mammals plus all extinct Mammals [1]
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See also
Additional images
 Lower extremity |
 Left patella - anterior aspect |
 Left patella - posterior aspect |
 Right knee-joint. The patellar reflex or knee-jerk is a Stretch reflex and is a Myotatic reflex. The lateral retinaculum is the Fibrous tissue on the outer side of the Kneecap (patella. 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. |
References
- ^ Herzmark MH (1938). "The Evolution of the Knee Joint". J Bone Joint Surg Am 20: 77-84.
External links
- The KNEEguru - educational site packed with knee content with sections on the patella
- SUNY Figs 12:01-15
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