What Do the Knees Do? How Do They Work?

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 Joint Basics, below.) 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.