Koplik spots Little spots inside the mouth that are highly characteristic of the early phase of measles (rubeola). The spots look like tiny grains of white sand, each surrounded by a red ring. They are often found on the inside of the cheek, opposite the first and second upper molars. See also measles.
Kok disease See hyperexplexia.
Koch postulates A set of criteria for judging whether a given microorganism is the cause of a given disease.
knuckle The top of the flexed finger joint.
knock-knees An abnormal curve of the legs that causes the knees to touch or nearly touch while the feet are apart. The problem may arise in the bone structure, or it may develop gradually as a result of muscle abnormalities. Knock-knees can cause movement difficulties, muscle and bone strain, and pain due to overstress on…
kneecap The patella, the small bone in the front of the knee. The patella is a little (sesamoid) bone, embedded in the tendon of insertion of the quadriceps muscle. If the patella is shattered beyond repair, it can be removed in an operation called a patellectomy and sometimes replaced with prosthetic material.
knee replacement A surgical procedure to relieve pain and increase function in people with severe damage to the knee joint. Knee replacement surgery may involve replacing the entire joint (total knee replacement) or only a portion of the joint (partial knee replacement). Damaged cartilage and bone from the surface of the knee joint are removed…
knee jerk The reflex that is tested by tapping just below the bent knee on the patellar tendon. Normally this causes the quadriceps muscle to contract and bring the lower leg forward. It has given rise to the saying “a knee-jerk reaction.” Also known as patellar reflex.
knee bursitis Inflammation of a fluid-filled sac (bursa) around the knee. See bursitis.
knee A joint that permits flexibility in the middle of the lower extremity. The thigh bone (femur) meets the large shin bone (tibia) to form the main knee joint. This joint has an inner (medial) and an outer (lateral) compartment. The kneecap (patella) joins the femur to form a third joint, called the patellofemoral joint….
Klippel-Trenaunay-Weber syndrome A rare congenital malformation syndrome of the vascular system characterized by enlargement of a single limb (asymmetric limb hypertrophy), varicose veins, abnormal connections in the vasular system (arteriovenous malformations), and abnormal nests of blood vessels that proliferate inappropriately and excessively (hemangiomata, or port-wine stains), and pigmented moles on the skin (nevi). Abbreviated KTW…
Klippel-Feil syndrome A congenital disorder involving the fusion of any two of the 7 neck (cervical) vertebrae. Affected individuals have a short neck, low hairline at the nape of the neck, and limited movement of the head. Klippel-Feil syndrome is due to a defect in the early development of the spinal column in the neck…