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(tō″mŏ-sin′thĕ-sĭs) [tomo- + synthesis] A three-dimensional imaging technique in which individual images of an organ (such as the breast) are captured and then digitally reconstructed to display non-overlapping sliced views. The technique exposes patients to less radiation that CT scanning, and improves the sensitivity and specificity of standard mammography.


[Gr. -tomos, cut, cutting + -ia] Suffix meaning cutting, incision.


(tōn) [L. tonus, a stretching] 1. That state of a body or any of its organs or parts in which the functions are healthy and normal. In a more restricted sense, the resistance of muscles to passive elongation or stretch. 2. Normal tension or responsiveness to stimuli, as of arteries or muscles, seen particularly in involuntary muscle (such as the sphincter of the urinary bladder). SYN: tonicity. (2). A musical or vocal sound.

muscular t. The state of slight contraction usually present in muscles that contributes to posture and coordination; the ability of a muscle to resist a force for a considerable period without change in length.

pure t. A sound composed of a single frequency. It has no overtones and no harmonics and can be represented graphically by a sinusoidal wave (a wave having the shape of the trigonometric sine curve y= sin x).

tone deafness

SEE: under deafness.




(tŭng) A freely movable muscular organ that lies partly in the floor of the mouth and partly in the pharynx. It is the organ of taste and contributes also to chewing, swallowing, and speech. SEE: illus.





ANATOMY: The tongue consists of a body and root and is attached by muscles to the hyoid bone below, the mandible in front, the styloid process behind, and the palate above, and by mucous membrane to the floor of the mouth, the lateral walls of the pharynx, and the epiglottis. A median fold (frenulum linguae) connects the tongue to the floor of the mouth. The surface of the tongue bears numerous papillae of three types: filiform, fungiform, and circumvallate (or vallate). Taste buds are present on the surfaces of many of the papillae, esp. the vallate papillae. Mucous and serous glands (lingual glands) are present; their ducts open on the surface. The lingual tonsils are lymphatic tissue on the base of the tongue. A median fibrous septum extends the entire length of the tongue.

Arteries: The lingual, exterior maxillary, and ascending pharyngeal arteries supply blood to the tongue. Muscles: Extrinsic muscles include genioglossus, hypoglossus, and styloglossus; intrinsic muscles consist of four ...

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