Images of the Knee

Gallery of Images, Photos, and X-Rays of the Knee


The Knee Joint

knee anatomy
Jeannot Olivet / Getty Images

The knee is one of the most commonly injured joints in the body. The knee joint is the junction of the thigh and the leg (part of the lower extremity). 

  • The femur (thigh bone) contacts the tibia (shin bone) at the knee joint. 
  • The patella (kneecap) sits over the front of the knee joint. 
  • Four major ligaments connect the bones and stabilize the knee joint

In the image above, the physician is pointing to the anterior cruciate ligament, or ACL, one of these important ligaments.


Inside the Joint


Inside the knee joint is a smooth cover on the ends of the bone called articular cartilage. 

Between the articular cartilage layer, is a shock absorbing cushion called meniscus cartilage

When people talk about knee cartilage, they may be talking about either the meniscus cartilage or the articular cartilage.


Bones of the Lower Extremity

lower extremity
Science Picture Co / Getty Images

The lower extremity includes the femur, the tibia, and foot and ankle bones. 

We call the segment between the hip and knee the thigh, and we call the segment between the knee and ankle the leg. 

Some people confuse the words leg and lower extremity, but in anatomic terms the leg spans only the distance from the knee to the ankle.


AP Knee X-Ray

Image © Jonathan Cluett, MD

An X-ray is one of the most common imaging tests used to diagnose a knee problem.

The image here is a front-to-back view of the knee joint, also called the AP view. (AP stands for anteroposterior, meaning the image is directed from the front to the back of the knee joint.)


Lateral Knee X-Ray

Image © Medical Multimedia Group

While an AP X-ray looks from front-to-back of the knee joint, a lateral view looks from the side of the joint. 

Lateral X-rays are particularly helpful at seeing the kneecap, or patella, and the cartilage space behind the kneecap.


Knee Arthritis

X-ray showing arthritic knees
Science Photo Library - DR P. MARAZZI/Brand X Pictures/Getty Images

Arthritis is a condition that causes pain and inflammation in joints.

Many different types of arthritis can occur in the knees, the most common of which is called osteoarthritis. People often use the words "wear-and-tear" to describe osteoarthritis, as it occurs when the cartilage between joints wears away, causing pain, stiffness, and trouble moving.


Knee Replacement

P. Marazzi / Getty Images

Knee replacement surgery is commonly used to treat pain and mobility issues caused by severe arthritis. 

During the procedure, damaged cartilage and bone are removed and replaced with a new implant, made of plastic or metal (or both), to restore the function of the knee.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Boston Medical Center. Common Knee Injuries.

  2. Harvard Health Publishing. X-ray may be best screening tool for diagnosing knee pain.

  3. Lee Y. C. (2013). Effect and treatment of chronic pain in inflammatory arthritis. Current rheumatology reports15(1), 300. doi: 10.1007/s11926-012-0300-4

  4. Centers for Disease Control and Prevention. Osteoarthritis (OA).

  5. Carr AJ, Robertsson O, Graves S, et al. Knee replacement. The Lancet. 2012;379(9823):1331-1340. doi: 10.1016/s0140-6736(11)60752-6

  6. The Cleveland Clinic. Total Knee Replacement Surgery.

Additional Reading

By Jonathan Cluett, MD
Jonathan Cluett, MD, is board-certified in orthopedic surgery. He served as assistant team physician to Chivas USA (Major League Soccer) and the United States men's and women's national soccer teams.