Also found in: Dictionary, Thesaurus, Encyclopedia.
Related to tuberculum: Tuberculum sellae, Tuberculum sellæ
1. a nodule or small eminence, especially one on a bone, for attachment of a tendon; see also tuber and tuberosity. Called also tuberculum. adj., adj tuber´cular, tuber´culate.
2. a small, rounded nodule produced by the bacillus of tuberculosis (Mycobacterium tuberculosis). It is made up of small spherical cells that contain giant cells and are surrounded by spindle-shaped epithelioid cells.
fibrous tubercle a tubercle of bacillary origin that contains connective tissue elements.
Ghon tubercle Ghon focus.
mental tubercle a prominence on the inner border of either side of the mental protuberance of the mandible.
miliary tubercle one of the many minute tubercles formed in many organs in acute miliary tuberculosis.
pubic tubercle a prominent tubercle at the lateral end of the pubic crest.
supraglenoid tubercle one on the scapula for attachment of the long head of the biceps muscle.
1. A nodule, especially in an anatomic, not pathologic, sense.
2. A circumscribed, rounded, solid elevation on the skin, mucous membrane, surface of an organ, or the surface of a bone, the latter giving attachment to a muscle or ligament.
3. dentistry a small elevation arising on the surface of a tooth. Synonym(s): tuberculum [TA]
4. A granulomatous lesion due to infection by Mycobacterium tuberculosis. Although somewhat variable in size (0.5-3 mm in diameter) and in the proportions of various histologic components, tubercle's tend to be fairly well circumscribed, spheroid, firm lesions that usually consist of three irregularly outlined but moderately distinct zones: 1) an inner focus of necrosis, coagulative at first, which then becomes caseous; 2) a middle zone that consists of a fairly dense accumulation of large mononuclear phagocytes (macrophages), frequently arranged somewhat radially (with reference to the necrotic material) resembling an epithelium, and hence termed epithelioid cells; multinucleated giant cells of Langhans type may also be present; and 3) an outer zone of numerous lymphocytes, and a few monocytes and plasma cells. In instances in which healing has begun, a fourth zone of fibrous tissue may form at the periphery. Morphologically indistinguishable lesions may occur in diseases caused by other agents; many observers use the term nonspecifically, that is, with reference to any such granuloma; other clinicians use tubercle only for tuberculous lesions, and then designate those of undetermined causes as epithelioid-cell granulomas.
[L. tuberculum, dim. of tuber, a knob, a swelling, a tumor]
tuberculum/tu·ber·cu·lum/ (-lum) pl. tuber´cula [L.] tubercle (2).
tuberculum arthri´ticum a gouty concretion in a joint.
tuberculum doloro´sum a painful nodule or tubercle.
a tubercle, nodule, or rounded elevation.
tu·ber·cu·lum, pl. tubercula (tū-bĕr'kyū-lŭm, -lă) [TA]
1. Synonym(s): tubercle (1) .
2. A circumscribed, rounded, solid elevation on the skin, mucous membrane, or surface of an organ.
3. A slight elevation from the surface of a bone giving attachment to a muscle or ligament.
[L. dim. of tuber, a knob, swelling, tumor]
pl. tubercula [L.] see tubercle.