Dictionary

mediastinotomy The surgical opening of the mediastinum. See also mediastinum; mediastinoscopy.

mediastinoscopy A procedure in which the physician inserts a tube into the chest to view the organs in the mediastinum. The tube is inserted through an incision above the breastbone.

median The middle, as in the median strip in a highway. For example, the median nerve is the nerve the runs through the middle of the wrist.

medial meniscus of the knee A thickened, crescent-shaped cartilage pad in the inner portion of the joint formed by the femur (the thigh bone) and the tibia (the shin bone). The medial meniscus is in the inner side, whereas the lateral meniscus is in the outer side of this knee joint. The meniscus acts as…

medial collateral ligament of the knee The ligament that straps the inner side of the knee joint, providing stability and strength. See also knee.

meconium ileus Obstruction of the intestine (ileus) due to overly thick meconium. Meconium ileus results from a deficiency of trypsin and other digestive enzymes from the pancreas, as in cystic fibrosis.

meconium Dark, sticky material that is normally present in the intestine at birth and passed in the feces after birth, after trypsin and other enzymes from the pancreas have acted on it. The passage of meconium before birth can be a sign of fetal distress.

Meckel diverticulum See diverticulum, Meckel.

meatus, female urethral The meatus (opening) of the female urethra, the transport tube that leads from the bladder to discharge urine outside the body. The female urethral meatus is above the vaginal opening.

meatus An opening or a passageway. For example, the meatus of the ear is the opening to the ear canal.

measly tapeworm See Taenia solium.

measles immunization A vaccine for measles only. Single-virus vaccines are sometimes used in children with known or suspected brain disorders or compromised immune systems, and they are generally given after 1 year of age. For other children, the measles vaccine is usually administered as a multivirus vaccine (MMR or MMRV) along with vaccines for mumps,…