Knee

In <a href="/facts/Human/rlcTENsr">humans</a> and other <a href="/facts/Primate/Hl8RNE2X">primates</a>, the knee joins the <a href="/facts/Thigh/HAGbp2M9">thigh</a> with the <a href="/facts/Leg/3W0vcemY">leg</a> and consists of two <a href="/facts/Joint/D70qxsey">joints</a>: one between the <a href="/facts/Femur/uVyTwj4l">femur</a> and <a href="/facts/Tibia/YXQ0F48L">tibia</a> (tibiofemoral joint), and one between the femur and <a href="/facts/Patella/3m1PL3G1">patella</a> (patellofemoral joint). It is the largest joint in the human body. The knee is a modified <a href="/facts/Hinge_joint/4XWYJGkz">hinge joint</a>, which permits <a href="/facts/Flexion/KmBVfcPk">flexion</a> and <a href="/facts/Extension_(kinesiology)/KmBVfcPk">extension</a> as well as slight internal and external rotation. The knee is vulnerable to injury and to the development of <a href="/facts/Osteoarthritis/Iy1wDA1B">osteoarthritis</a>.
It is often termed a compound joint having tibiofemoral and patellofemoral components. (The <a href="/facts/Fibular_collateral_ligament/FSTBzrra">fibular collateral ligament</a> is often considered with tibiofemoral components.)

Knee open-in-new

Knee