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Patellar dislocations occur with significant regularity, particularly in young female athletes. It involves the patella sliding out of its position on the knee, most often laterally, and may be associated with extremely intense pain and swelling. The patella can be tracked back into the groove with
428:
layer at the location of an emargination. Previously, bipartite patellas were explained as the failure of several ossification centres to fuse, but this idea has been rejected. Partite patellas occur almost exclusively in men. Tripartite and even multipartite patellas occur.
381:, which can reach a maximal thickness of 6 mm (0.24 in) in the centre at about 30 years of age. Owing to the great stress on the patellofemoral joint during resisted knee flexion, the articular cartilage of the patella is among the thickest in the human body.
592:
The kneecap is prone to injury because of its particularly exposed location, and fractures of the patella commonly occur as a consequence of direct trauma onto the knee. These fractures usually cause swelling and pain in the region, bleeding into the joint
432:
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. Four main types of articular surface can be distinguished:
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have kneecaps, contrary to what was thought. This raises the possibility that the kneecap arose 350 million years ago when tetrapods first appeared, but that it disappeared in some animals.
800:
Palmu, S.; Kallio, P.E.; Donell, S.T.; Helenius, I.; Nietosvaara, Y. (2008). "Acute patellar dislocation in children and adolescents: A randomized clinical trial".
1177:
597:), and an inability to extend the knee. Patella fractures are usually treated with surgery, unless the damage is minimal and the extensor mechanism is intact.
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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
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have only rudimentary, non-ossified patellae although a few species possess a bony patella. A patella is also present in the living
873:
Melloni, Pietro; Veintemillas, Maite; Marin, Anna; Valls, Rafael (2013). "Imaging
Patellar Complications After Knee Arthroplasty".
1692:
502:, which discourages lateral dislocation during flexion. The retinacular fibres of the patella also stabilize it during exercise.
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centre develops at the age of 3–6 years. The patella originates from two centres of ossification which unite when fully formed.
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with the femur and is subdivided into a medial and a lateral facet by a vertical ledge which varies in shape.
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The lower part of the posterior surface has vascular canaliculi filled and is filled by fatty tissue, the
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The front and back surfaces are joined by a thin margin and towards centre by a thicker margin. The
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roughly triangular in shape, with the apex of the patella facing downwards. The apex is the most
260:(i.e., embedded within a tendon or a muscle) in the body. Babies are born with a patella of soft
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an extension of the knee, and therefore sometimes returns into the proper position on its own.
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In the adult the articular surface is about 12 cm (1.9 sq in) and covered by
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is a low-riding patella. A long-standing patella baja may result in extensor dysfunction.
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The primary functional role of the patella is knee extension. The patella increases the
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formation. This can be the cause of chronic pain when formed on the patella.
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325:. The lower third culminates in the apex which serves as the origin of the
225:(thigh bone) and covers and protects the anterior articular surface of the
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are attached to outer lateral and medial borders of patella respectively.
53:
1155:
838:
Dath, R.; Chakravarthy, J.; Porter, K.M. (2006). "Patella
Dislocations".
813:
638:
622:
494:. The patella is stabilized by the insertion of the horizontal fibres of
319:
1137:"patella - Origin and meaning of patella by Online Etymology Dictionary"
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is an unusually small patella that develops out of and above the joint.
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Most commonly the medial articular surface is smaller than the lateral.
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European
Surgical Orthopaedics and Traumatology: The EFORT Textbook
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can exert on the femur by increasing the angle at which it acts.
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is the formation of new bone onto a bone, as a result of excess
491:
420:, a "missing piece") are common laterally on the proximal edge.
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661:, and a patella is not present. In 2017 it was discovered that
1035:. Philadelphia, PA: Holt-Saunders International. p. 205.
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Sometimes both articular surfaces are virtually equal in size.
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joint. The patella is found in many tetrapods, such as
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Color Atlas of Human
Anatomy, Vol. 1: Locomotor System
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1031:Romer, Alfred Sherwood; Parsons, Thomas S. (1977).
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544:is a high-riding (superiorly aligned) patella. An
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299:attaches to the base of the patella., with the
424:are the result of an ossification of a second
110:Present at the joint of femur and tibia fibula
37:"Kneecap" redirects here. For other uses, see
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677:originated in the late 17th century from the
303:muscle attaching to the base itself, and the
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562:Insall-Salvati ratio (A divided by B).
490:, which contracts to extend/straighten the
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570:helps to indicate patella baja on lateral
52:
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1091:
1076:"On the presence of the patella in frogs"
1074:Virginia Abdala; et al. (Jul 2017).
370:The upper three-quarters of the patella
911:Yuranga Weerakkody and Frank Gaillard.
752:
645:. In other tetrapods, including living
331:
268:into bone at about four years of age.
256:In humans, the patella is the largest
184:
43:
1057:"Frogs have hidden, ancient kneecaps"
7:
450:the central ledge is only indicated.
443:Occasionally, the medial surface is
202:
25:
993:"The Evolution of the Knee Joint"
802:Journal of Bone and Joint Surgery
408:of the patella can be seen – the
341:Human left patella from the front
27:Kneecap, bone covering knee joint
970:. Springer. pp. 2766–2784.
358:
346:
334:
318:. The middle third has numerous
217:, is a flat, rounded triangular
73:
482:The patella is attached to the
943:"TKA in Patella Baja (Infera)"
353:Human left patella from behind
1:
941:Douglas Dennis (2017-02-25).
498:and by the prominence of the
365:Flexion and extension of knee
578:0.8 indicates patella baja.
221:which articulates with the
1709:
1006:(1): 77–84. Archived from
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36:
29:
852:10.1191/1460408606ta353ra
488:quadriceps femoris muscle
297:quadriceps femoris muscle
179:
51:
771:Platzer, Werner (2004).
704:, meaning shallow dish.
621:The patella is found in
181:Anatomical terms of bone
39:Kneecap (disambiguation)
32:Patella (disambiguation)
1693:Bones of the lower limb
1255:intertrochanteric crest
546:attenuated patella alta
500:lateral femoral condyle
1287:intertrochanteric line
1250:intertrochanteric line
714:anatomical terminology
695:
687:
563:
532:
413:
1080:The Anatomical Record
875:Arthroplasty - Update
561:
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506:Clinical significance
399:
386:infrapatellar fat pad
213:), also known as the
1471:Posterior colliculus
1000:J Bone Joint Surg Am
991:Herzmark MH (1938).
814:10.2106/JBJS.G.00072
568:Insall-Salvati ratio
517:Patellar dislocation
416:Emarginations (i.e.
406:anatomical variation
30:For other uses, see
1466:Anterior colliculus
1373:intercondylar fossa
1033:The Vertebrate Body
966:Bentley, G (2014).
731:Lateral retinaculum
1560:calcaneal tubercle
1555:sustentaculum tali
1424:intercondylar area
1305:gluteal tuberosity
1292:upper intermediate
1233:greater trochanter
1141:www.etymonline.com
1125:New Shorter Oxford
712:This article uses
564:
536:Vertical alignment
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459:In the patella an
422:Bipartite patellas
418:patella emarginata
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301:vastus intermedius
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1500:lateral malleolus
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1329:adductor tubercle
1260:quadrate tubercle
1245:lesser trochanter
1086:(10): 1747–1755.
892:978-953-51-0995-2
623:placental mammals
477:quadriceps tendon
410:bipartate patella
327:patellar ligament
286:patellar ligament
276:The patella is a
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16:(Redirected from
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1461:medial malleolus
1402:Gerdy's tubercle
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69:Pronunciation
67:
62:
55:
50:
45:
40:
33:
19:
1592:intermediate
1520:
1515:
1406:
1355:
1338:
1300:
1291:
1283:upper medial
1282:
1278:linea aspera
1140:
1131:
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1120:
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1079:
1069:
1060:
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1032:
1026:
1015:. Retrieved
1008:the original
1003:
999:
986:
967:
961:
950:. Retrieved
947:Orthobullets
946:
922:. Retrieved
916:
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604:
595:hemarthrosis
591:
567:
565:
553:patella baja
552:
550:
542:patella alta
541:
539:
531:Patella baja
524:
520:
481:
470:
461:ossification
458:
431:
417:
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383:
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214:
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196:
150:A02.5.05.001
125:
1609:Metatarsals
1445:soleal line
1339:epicondyles
1103:11336/58233
918:Radiopaedia
655:lepidosaurs
511:Dislocation
455:Development
445:hypoplastic
372:articulates
115:Identifiers
1672:Categories
1440:tuberosity
1017:2007-11-17
952:2019-02-08
924:2018-01-16
747:References
679:diminutive
647:amphibians
635:monotremes
631:marsupials
323:canaliculi
249:, or most
58:Right knee
1653:Phalanges
1582:cuneiform
1572:navicular
1550:calcaneus
1191:human leg
899:CC-BY-3.0
860:208269986
721:Knee pain
673:The word
669:Etymology
649:and most
607:exostosis
601:Exostosis
475:that the
392:Variation
379:cartilage
316:exostoses
272:Structure
262:cartilage
1407:condyles
1356:condyles
1307: /
1112:28667673
846:: 5–11.
822:18310694
708:See also
681:form of
651:reptiles
641:and the
639:platypus
582:Fracture
473:leverage
467:Function
400:In this
320:vascular
282:inferior
251:reptiles
211:patellas
207:patellae
18:Patellar
1678:Patella
1597:lateral
1516:patella
1412:lateral
1361:lateral
1344:lateral
1189:of the
675:patella
643:echidna
629:; most
611:calcium
486:of the
295:of the
215:kneecap
199:patella
138:D010329
126:patella
107:Origins
64:Details
47:Patella
1587:medial
1577:cuboid
1542:Tarsus
1492:Fibula
1417:medial
1366:medial
1349:medial
1110:
1039:
974:
889:
858:
840:Trauma
820:
783:
777:Thieme
696:patena
688:patina
637:, the
572:X-rays
484:tendon
293:tendon
266:ossify
247:whales
1646:Other
1567:talus
1509:Other
1433:shaft
1387:Tibia
1270:shaft
1238:fossa
1221:fovea
1199:Femur
1187:Bones
1011:(PDF)
996:(PDF)
856:S2CID
702:paten
683:Latin
663:frogs
659:tibia
627:birds
404:, an
402:X-ray
239:birds
223:femur
185:[
174:24485
121:Latin
1683:Knee
1533:Foot
1521:apex
1228:neck
1216:head
1108:PMID
1037:ISBN
972:ISBN
887:ISBN
818:PMID
781:ISBN
625:and
576:<
566:The
492:knee
307:and
243:dogs
241:and
235:cats
231:mice
227:knee
219:bone
197:The
162:1390
145:TA98
133:MeSH
1637:5th
1632:4th
1627:3rd
1622:2nd
1617:1st
1098:hdl
1088:doi
1084:300
879:doi
848:doi
810:doi
700:or
692:or
605:An
209:or
203:pl.
169:FMA
157:TA2
1674::
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99:/
96:ə
93:l
90:ɛ
87:t
84:ˈ
81:ə
78:p
75:/
41:.
34:.
20:)
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