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(masʹtĕr) In robotic surgery, a device driven by the hand movements of the surgeon or interventionist. The movements of the master are mimicked, reduced, or refined by the surgical instrument (the “slave”) in the operative field.

Masters disease

(masʹtĕrz) Southern tick–associated rash illness.

Master two-step test

[Arthur Matthew Master, U.S. physician, 1895–1973] A standardized exercise test formerly used to assess cardiopulmonary function. It has been replaced by exercise treadmill testing, pharmacological stress testing, and other tests of fitness and cardiovascular reserve. SEE: exercise tolerance test.

mastery motivation

The willingness to endure challenges in order to achieve personal or professional goals.


(masʹtik) [L. mastichum, mastiche fr Gr. mastichē, chewing gum, mastic] 1. A small evergreen shrub (Pistacia lentiscus), native to the Mediterranean and cultivated for its resin. 2. The resin or gum from this tree. SEE: mastic gum.


(măs-tĭ-kāʹshŭn) [L. masticare, to chew] Chewing. Coordination of the large temporal, masseter, pterygoid muscles, and other smaller muscles of the mandible and tongue is required, under the influence of the mandibular division of cranial nerve V. masticatory (măsʹtĭk-ă-tōʺrē), adj.

masticatory apparatus

(măsʹtĭ-kă-tŏrʺē ăpʺă-rătʹĭs, -rāʹtĭs) The teeth, jaws, muscles of mastication, and the temporomandibular joints; used for chewing.


(măsʺtĭ-gŏfʹō-ră) Formerly a division of protozoa characterized by one or more flagella. Now called Zoomastigophora, a phylum of the kingdom Protista.


(măsʹtĭ-gōt) A member of the protozoon group formerly called Mastigophora.


(mas-tītʹĭs) [masto- + -itis] Inflammation or infection of the breast.

cystic m. Mastitis resulting in formation of cysts that give the breast a nodular feeling upon palpation.

granulomatous m. A rare inflammatory disease of the breast, often presenting as a tender mass. Symptoms usually appear within 2 years after a pregnancy. Even with mammography or ultrasonography, granulomatous mastitis may be difficult to distinguish from breast cancer without biopsy. Once the diagnosis is definitively established, the disease is treated with corticosteroids or by surgical removal of the mass.

lactation m. Mastitis that occurs during breast-feeding, typically in the second or third postpartum week. Lactation mastitis may occur at any age. It occurs in about 1% of postpartum women, primarily in breast-feeding primiparas, but it can occur in nonlactating women and, rarely, in men. SYN: lactational m.

 ETIOLOGY: Infection may be due to entry of disease-producing germs through cracks in the nipple. Most commonly, the offending microorganism is Staphylococcus aureus. Other predisposing factors include blocked ...

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