YOUR KNEE AND HOW IT WORKS: BONE
Bones provide strength, stability, and flexibility. They are shaped in such a way to allow you to flex and extend. There are four bones around the knee.
The femur, also known as the thigh bone, is the longest, largest, and strongest bone in the body. The femur runs down from the pelvis to the knee joint, where it meets with the tibia. The round knobs at the end of the bone are called condyles.
The tibia, also known as the shinbone, runs from the knee down to the ankle.
The fibula is a long, thin bone that begins below the knee and runs down the side of the leg (adjacent to the tibia) and ends at the ankles by forming a bulbous end called the lateral malleolus, the round knobs on the outside of your ankle. It is smaller and thinner than the tibia or femur.
The patella, also called the kneecap, is a small, flat triangular-shaped bone about 2 to 3 inches wide and 3 to 4 inches long that moves and rotates with the knee. The patella moves as the leg moves—it glides up and down the thigh bone almost as if it's on a track. Although it is small, the patella is a critical player in the mechanics of the knee. The patella is very important for muscle strength by giving the muscles the extra leverage they need to straighten the leg. The patella also cushions and protects the other bones of the joint. For example, in the case of a fall or blow to the knee, the patella may prevent the condyles (bony knobs) of the tibia or femur from being injured. If the patella slides off track even by a tiny amount, it can cause great pain and may result in permanent injury. If the kneecap partially comes off its track, it's called a subluxation. If the kneecap is entirely off track—for example, it sits way off to the side instead of in the center—it's called a dislocation.
healthy bones Osteoporosis Rheumatic