Dictionary

miscarriage Inadvertent loss of a pregnancy before the fetus is viable. A considerable proportion of pregnancies end in miscarriage. Also known as spontaneous abortion.

miosis Contraction of the pupil. The opposite of miosis is mydriasis.

minoxidil A medication (brand names: Loniten, Rogaine) that was originally developed to treat high blood pressure as an oral medication and is now also used in topical form to promote hair growth.

minor salivary gland A small gland that produces saliva. The mouth and palate contain numerous minor salivary glands.

minor In general, something that is less than something else. For example, the teres minor muscle is smaller than the teres major muscle.

mini-stroke See transient ischemic attack.

minimally invasive surgery A type of surgery that is done through small incisions through which instruments and imaging devices are passed; sometimes called laparoscopic surgery. Minimally invasive surgery is performed in many different surgical specialties. For patients, minimally invasive surgery has the advantages of a lower rate of blood loss and other complications, smaller surgical…

mineralocorticoid A group of hormones that regulate the balance of water and electrolytes (ions such as sodium and potassium) in the body. The mineralocorticoid hormones act on the tubules of the kidney. The most important mineralocorticoid hormone is aldosterone.

miliary tuberculosis The presence of numerous sites of tuberculosis infection, each of which is minute, due to dissemination of infected material through the bloodstream in a process somewhat like the metastasis of a malignancy.

miliary aneurysm A tiny aneurysm. Miliary aneurysms tend to affect minute arteries in the brain or in the retina of the eye. They can bleed and lead to impaired function of the brain or eye. See also aneurysm.

migrainous neuralgia See cluster headache.

migraine headache The most common type of vascular headache, thought to be caused by abnormal sensitivity of arteries in the brain to various triggers that result in arterial spasms. Other arteries in the brain and scalp then open, and throbbing pain is perceived in the head. The tendency to migraine is inherited and appears to…