What Do the Knees Do? How Do They Work?

The knee is the joint where the bones of the upper leg meet the bones of the lower leg, allowing hinge-like movement while providing stability and strength to support the weight of the body. Flexibility, strength, and stability are needed for standing and for motions like walking, running, crouching, jumping, and turning.

Several kinds of supporting and moving parts, including bones, cartilage, muscles, ligaments, and tendons, help the knees do their job (see box “Joint Basics”). Each of these structures is subject to disease and injury. When a knee problem affects your ability to do things, it can have a big impact on your life. Knee problems can interfere with many things, from participation in sports to simply getting up from a chair and walking.

Source: NIAMS (NIH)1

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What Are the Parts of the Knee?

Like any joint, the knee is composed of bones and cartilage, ligaments, tendons, and muscles.

Source: NIAMS (NIH)2

Introduction: Knee

The knee capsule is a protective, fiber-like structure that wraps around the knee joint. Inside the capsule, the joint is lined with a thin, soft tissue called synovium.

Source: NIAMS (NIH)3

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Knee: A region of the lower extremity immediately surrounding and including the Knee Joint.4

Anatomy Articles

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Symptom Articles

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  1. Source: NIAMS (NIH): Health_Info/ Knee_Problems/ default.asp
  2. ibid.
  3. ibid.
  4. Source: MeSH (U.S. National Library of Medicine)
  5. Source: MedLinePlus (NIH): woundsandinjuries.html
  6. Source: NIAMS (NIH): Health_Info/ Knee_Problems/ default.asp

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.