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Symptoms > Arthritis Symptoms By Body Part > The Knee > Knee Anatomy
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Anatomy of the Knee

The knee is the joint where the bones of the lower and upper legs meet. The largest joint in the body, the knee moves like a hinge, allowing you to sit, squat, walk or jump.

The knee consists of three bones:

• femur – the upper leg bone, or thigh bone
• tibia – the bone at the front of the lower leg, or shin bone
• patella – the thick, triangular bone that sits over the other bones at the front of the knee, or kneecap.

The ends of the bones are covered with a layer of cartilage, a slick, elastic material that absorbs shock and allows the bones to glide easily against one another as they move.

Between the tibia and femur bone are two crescent-shaped pads of connective tissue that reduce friction and disperse the weight of the body across the joint. They are:

• The lateral meniscus, situated at the outside of the knee.
• The medial meniscus, situated on the inside of the knee.

The bones are held together by a joint capsule, which consists of two distinct layers – an outer layer of dense connective tissue and an inner membrane, called the synovium, which secretes a fluid to lubricate the joint. 

The outer layer of the capsule is attached to the ends of the bones and is supported by these ligaments and tendons:

• quadriceps tendon, which attaches the quadriceps to the patella
• medial collateral ligament (MCL),
 which gives stability to the inner part of the knee
• lateral collateral ligament (LCL), which stabilizes the outer part of the knee
• anterior cruciate ligament (ACL), which is located in the center of the knee and prevents excessive forward movement of the tibia
• posterior cruciate ligament (PCL),
which is located in the center of the knee and prevents excessive backward shifting of the knee.

Two groups of muscles support the knee. They are:

• Hamstrings – muscles on the back of the thigh, which run from the hip to just below the knee and work to bend the knee.  
• Quadriceps
– four muscles on front of the thigh that run from the hip to the knee and straighten the knee from a bent position.

rama
08 Feb 2012, 04:18
I found a lump behind the knee at the place of folding. My doc said that it is an early symptom of osteoarthritis and said that the lump remains so and can only delay the degeneration through exercise. Is there any other cure for it? I am 52.
kasisenthivel
07 Jul 2011, 07:45
Without diagram,it is very difficult to understand the details.Please arrange for the same.Thanking you.
Yours sincerly
Senthivel
yolanda clark
24 Nov 2010, 08:00
where are the diagrams???????
Judy
16 Sep 2010, 09:36
Diagrams would be nice for this section.
jim
25 Aug 2010, 13:55
I think it woud be nice to have some diagrams of the knee for this section.
Lillian
23 Aug 2010, 10:28
How can I teach my right knee to go straight again? I have been favoring it b/c of a hyper-extension in my ankle and my left leg is back to functioning fairly well but my right knee is bent and I cannot straighten it out to carry the weight again.

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