Orthopedics Hip & Knee Images of the Knee Gallery of Images, Photos, and X-Rays of the Knee By Jonathan Cluett, MD twitter linkedin 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. Learn about our editorial process Jonathan Cluett, MD Medically reviewed by Medically reviewed by Stuart Hershman, MD on July 05, 2020 linkedin Stuart Hershman, MD, is board-certified in orthopaedic surgery. He is the director of adult spinal deformity & complex spinal reconstruction at Massachusetts General Hospital and is on the faculty at Harvard Medical School. Learn about our Medical Review Board Stuart Hershman, MD on July 05, 2020 Print 1 The Knee Joint 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. Common Causes of Knee Pain 2 Inside the Joint SPRINGER MEDIZIN / Getty Images 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. 3 Bones of the 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. 4 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.) 5 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. 6 Knee Arthritis 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. 7 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. Surgery for Knee Injuries Was this page helpful? Thanks for your feedback! Dealing with joint pain can cause major disruptions to your day. Sign up and learn how to better take care of your body. Click below and just hit send! Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article 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. Joseph AM, Collins CL, Henke NM, Yard EE, Fields SK, Comstock RD. A multisport epidemiologic comparison of anterior cruciate ligament injuries in high school athletics. J Athl Train. 2013;48(6):810-817. doi:10.4085/1062-6050-48.6.03