Knee joint
Updates to Article Attributes
Body
was changed:
The knee joint is a modified hinge joint between the femur, tibia and patella. It is the largest synovial joint in the body and allows flexion and extension of the leg as well as some rotation in the flexed position.
Summary
- location: two condylar joints between femur and tibia; saddle joint between patella and femur
- blood supply: main supply are the genicular branches of the popliteal artery
- nerve supply: branches from the femoral, tibial, common peroneal and obturator nerves
- movement: flexion to 150°, extension to 5-10° hyperextension; rotation whilst in the flexed position to 10° actively and 60° passively
Gross anatomy
Articulations
Two condylar joints between the femur and tibia:
- medially: between a narrow and curved femoral condyle, and an oval tibial articular surface with a long anteroposterior length
- laterally: between a wide and flat femoral condyle; and a circular tibial articular surface
- the knee menisci are shaped accordingly
Saddle joint between the patella and femoral condyles:
- the patella is divided into lateral, middle and medial areas by ridges
- in extension: the lateral patella surface articulates with the lateral femoral condyle
- in flexion: the medial patella surface articulates with the medial femoral condyle and the middle patella surface faces the intercondylar notch
Attachments
- ligaments
- tendons
- knee menisci
- knee capsule
- knee synovial membrane
Relations
Blood supply
The knee is supplied by anastomoses of:
- five genicular branches of the popliteal artery (main supply)
- descending branch of the lateral circumflex femoral artery
- descending genicular branch of the femoral artery
- circumflex fibular branches of the posterior tibial artery
- anterior and posterior recurrent branches of the anterior tibial artery
Innervation
The nerve supply to the knee is derived from:
- branches of the femoral nerve to vastus medialis, intermedius, and lateralis
- genicular branches of the tibial and common peroneal nerves
- branch from the posterior division of the obturator nerve
Radiographic features
Plain radiograph
See knee radiograph (an approach)
Related pathology
- absent patella
- ACL ganglion cyst
- ACL mucoid degeneration
- anterior tibial translocation sign
- arcuate sign
- avulsion fractures of the knee
- bipartite patella
- chondromalacia patellae
- contrecoup injury of the knee
- jumper's knee
- meniscal cyst
- Osgood-Schlatter disease
- patella alta
- patella baja
patella cubiti- patellar instability
- patella fracture
- patellar sleeve fractures
- patellar tendon lateral femoral condyle friction syndrome
- patella tendon rupture
- patellar tooth sign
- pes anserinus bursitis
- reverse Segond fracture
- Segond fracture
- semimembranosus tendon avulsion fracture
- Sinding-Larsen-Johansson syndrome
- Stieda fracture (MCL avulsion fracture)
- tibial plateau fracture
- tibial pseudoarthrosis
- tibial tuberosity avulsion fracture
-<li><a href="/articles/patella-cubiti">patella cubiti</a></li>
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