kneecap

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pa·tel·la

, gen. and pl.

pa·tel·lae

(pa-tel'ă, -ē), [TA]
The large sesamoid bone, in the combined tendon of the quadriceps femoris, covering the anterior surface of the knee.
Synonym(s): kneecap
[L. a small plate, the kneecap, dim. of patina, a shallow disk, fr. pateo, to lie open]

kneecap

(nē′kăp′)
n.
1. See patella.
2. See kneepad.
tr.v. knee·capped, knee·capping, knee·caps
To cripple by shooting in the legs, especially in the knees.

kneecap

See patella.

pa·tel·la

, pl. patellae (pă-tel'ă, -ē) [TA]
The large sesamoid bone that covers the anterior surface of the knee. It is formed in the tendon of the quadriceps femoris muscle and is attached to the tibia by the patellar tendon.
Synonym(s): kneecap.
[L. a small plate, the kneecap, dim. of patina, a shallow disk, fr. pateo, to lie open]

patella

; kneecap large sesamoid embedded within quadriceps tendon at anterior aspect of knee joint; its cartilaginous internal facet articulates with knee joint; exerts pulley-like action within the patellar groove; acts as a fulcrum for quadriceps action, centralizing action of contributory muscles (i.e. rectus femoris, vastus intermedius, vastus lateralis and vastus medialis) (see Table 1); protects quadriceps tendon, allowing knee extensor apparatus to take high load (by lengthening the lever arm, and giving mechanical advantage to quadriceps)
Table 1: Muscles acting on the joints of the lower limb and foot
JointMuscleMuscle originMuscle insertion
Hip onlyAdductor longus
Adductor brevis
Adductor magnus
Psoas major
Iliacus
Pectineus
Gluteus minimus
Gluteus medius
Gluteus maximus (deep quarter)
Piriformis
Obturator externus
Obturator internus
Gemelli
Body of pubis
Body and inferior ramus of pubis
Inferior ramus of pubis
Lumbar vertebrae
Iliac fossa
Body and superior ramus of pubis
Ileum
Ileum
Sacrum
Sacrum
Obturator membrane
Internal surfaces of ileum, pubis
Ischium, sides of sciatic notch
Linea aspera of posterior femur
Linea aspera of posterior femur
Lower medial femur, adductor tubercle
Lesser trochanter
Femur, inferior to lesser trochanter
Posterior area of lesser trochanter
Anterior area greater trochanter
Lateral area greater trochanter
Gluteal tuberosity of femur
Greater trochanter
Trochanteric fossa
Medial area greater trochanter
Medial area greater trochanter
Hip and kneeBiceps femoris (long head)
Semimembranosus
Semitendinosus
Gracilis
Sartorius
Tensor fasciae lata
Rectus femoris
Gluteus maximus (superior three-quarters)
Ischial tuberosity
Ischial tuberosity
Ischial tuberosity
Body and inferior ramus of pubis
Anterior superior iliac spine
Anterior one-quarter of iliac crest
Anterior ileum
Posterior area of ileum and sacrum
Head of fibula
Posterior-area medial tibial condyle
Upper one-quarter medial tibia
Upper one-quarter medial tibia
Upper one-quarter medial tibia
Lateral condyle tibia via iliotibial tract
Patella, via quadriceps tendon
Lateral condyle tibia via iliotibial tract
Knee onlyVastus medialis
Vastus intermedius
Vastus lateralis
Biceps femoris (short head)
Popliteus
Anterior upper femur and tendon of adductor magnus
Anterior and lateral surfaces of body of femur
Greater trochanter and linea aspera of femur
Linea aspera
Lateral condyle of femur
Superior and medial surfaces of patella and capsule of knee joint
Superior surface of patella and suprapatellar bursa
Superior and lateral surfaces of patella and capsule of knee joint
Head of fibula
Posterior surface of upper tibia
Knee and ankleGastrocnemius
Plantaris
Lateral surface of lateral condyle and posterior surface of medial femoral condyle
Posterior surface of lateral femoral condyle
Calcaneum, via Achilles tendon
Calcaneum, via Achilles tendon (acts with gastrocnemius)
Ankle onlySoleusSoleal line and middle one-third of medial border of tibia and posterior surface of upper one-third fibulaCalcaneum, via Achilles tendon
Ankle and tarsusPeroneus longus
Peroneus brevis
Tibialis anterior
Tibialis posterior
Peroneus tertius
Lateral surface of upper two-thirds of lateral fibula
Lateral surface of lower two-thirds of lateral fibula
Lateral surface of upper one-half of tibia and local interosseous membrane
Upper one-half of tibia, fibula and local interosseous membrane
Anterior surface of distal one-quarter of fibula
Base of first metatarsal and lateral side of medial (first) cuneiform
Base of fifth metatarsal
Base of first metatarsal and inferomedial aspect of medial (first) cuneiform
Medial (first) cuneiform, inferior aspects of all tarsal bones (except the talus) and bases of second, third and fourth metatarsals
Dorsal shaft of fifth metatarsal
Tarsus and toesExtensor digitorum brevis
Flexor digitorum brevis
Flexor accessories (quadratus plantae)
Abductor hallucis
Abductor digiti minimi
Superior and anterior surfaces of the calcaneum
Medial process of calcaneal tuberosity
Plantar, medial and lateral aspects of calcaneum
Medial process of calcaneal tuberosity and flexor retinaculum
Calcaneal tuberosity
Dorsum of proximal phalanx of hallux, and extensor expansions of toes 2-4
Plantar, middle phalanges of toes 2-5
Tendon flexor digitorum longus
Medial side of proximal phalanx of hallux
Lateral side of proximal phalanx of fifth toe
Toes onlyDorsal interossei
Plantar interossei
Lumbricals
Flexor hallucis brevis
Adductor hallucis
Flexor digiti minimi brevis
Adjacent sides of metatarsals 1-5
Medial sides of metatarsals 3-5
Digital tendon slips of flexor digitorum longus
Medial plantar aspect of the cuboid
Bases of 2-4 metatarsals and transverse plantar ligament of 2-4 metatarsophalangeal joints
Base of fifth metatarsal
Lateral side of toes 2-4 and medial side toe 2
Medial sides of bases of proximal phalanges of toes 3-5
Extensor expansions toes 2-5
Medial and lateral sides of base of proximal phalanx of hallux
Lateral side of base of proximal side of hallux
Lateral side of base of proximal phalanx of toe 5

kneecap

see patella.