Arthritis: inflammation of a joint, usually accompanied by pain, swelling, and sometimes change in structure.
 
Arthroscopy: a minimally invasive diagnostic and treatment procedure used to visualize, diagnose, and treat problems inside a joint.
 
Anterior Cruciate Ligament (ACL): the ligament, located in the center of the knee, that controls rotation and forward movement of the tibia (shin bone).
 
Arthrogram: an xray to view bone structures following an injection of a contrast fluid into a joint area. When the fluid leaks into an area that it does not belong, disease or injury may be considered, as a leak would provide evidence of a tear, opening, or blockage.
 
Bursa: a sac filled with fluid located between a bone and a tendon or muscle.
 
Bursitis: repeated small stresses and overuse that cause the bursa to swell and become irritated.
 
Cartilage: a smooth material that covers bone ends of a joint to cushion the bone and allow the joint to move easily without pain.
 
Computed Tomography Scan (Also called a CT or CAT scan.): a diagnostic imaging procedure that uses a combination of xrays and computer technology to produce crosssectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs.
 
Dislocation: a dislocation occurs when extreme force is put on to the bones that form a particular joint, producing its separation.
 
Femur: thigh bone.
 
Inflammation: a normal reaction of living tissue to injury or damage.
 
Joint: structure where the ends of two or more bones meet.
 
Ligaments: a white, shiny, flexible band of fibrous tissue that binds joints together and connects various bones and cartilage.
 
Lateral Collateral Ligament (LCL): the ligament that gives stability to the outer knee.
 
Musculoskeletal System: the complex system that includes: bones, joints, ligaments, tendons, muscles, and nerves.
 
Magnetic Resonance Imaging (MRI): a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
 
Medial Collateral Ligament (MCL): the ligament that gives stability to the inner knee.
 
Menisci: two crescentshaped discs of connective tissue between the bones of the knees that act as shock absorbers to cushion the lower part of the leg from the weight of the rest of the body.
 
Osteoarthritis: a condition caused by wear and tear that causes inflammation of the joint, causing swelling, pain, and stiffness.
 
Osteoporosis: a condition that develops when bone is no longer replaced as quickly as it is removed.
 
Posterior Cruciate Ligament (PCL): the ligament, located in the center of the knee, that controls backward movement of the tibia (shin bone).
 
Prosthesis: an artificial body part replacement.
 
Rheumatoid Arthritis: an inflammatory disease that involves the lining of the joint (synovium). The inflammation often affects the joints of the hands and the feet and tends to occur equally on both sides of the body.
 
Synovium: a fibrous envelope that produces a fluid to help to reduce friction and wear in a joint.
 
Synovial Fluid: a clear, sticky fluid that is released by the synovial membrane and acts as a lubricant for joints and tendons.
 
Tendon: a cord that connects muscle to bone or other tissue.
 
Tendonitis: an inflammation in a tendon.
 
Tibia: shin bone or larger bone of the lower leg.
 
Ultrasound: a diagnostic technique which uses highfrequency sound waves to create an image of the internal organs.
 
X-ray: a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.