tubercle

1. A small rounded projecting part or outgrowth, such as a wartlike excrescence on the roots of some leguminous plants or a knoblike process in the skin or on a bone.
2. Pathology. A nodule or swelling, especially a mass of lymphocytes and epithelioid cells forming the characteristic lesion of tuberculosis.

[Latin tūberculum, diminutive of tūber, lump. See tuber.]

A small rounded nodule or elevation on the surface of the skin, bone, or other tissue.

A nodule or small rounded process on a bone, smaller than a tuberosity.

1. a small, rounded nodule produced by the bacillus of tuberculosis (Mycobacterium bovis). It is made up of small spherical masses that contain giant cells and are surrounded by spindle-shaped epithelioid cells.
2. a nodule or small eminence, especially one on a bone, for attachment of a tendon. See also cuneate tubercle.

• dysgonic t. (1) — one from which it is difficult to culture mycobacteria, typical of Mycobacterium bovis.
• eugonic t. (1) — one from which mycobacteria can be isolated with ease. Typical of Mycobacterium avium.
• fibrous t. (1) — a tubercle of bacillary origin that contains connective tissue elements.
• genital t. — see phallic tubercle (below).
• gracile t. — a small swelling; used as an anatomical landmark; also an attachment for the gracilis nucleus in the medulla oblongata.
• humerus t. — the point of the shoulder; the greater tubercle on the head of the humerus.
• intercondylar t's — situated on the intercondylar eminence on the head of the tibia, there are medial and lateral tubercles. Called also intercondylar eminences.
• intermediate humerus t. — a small ridge between the greater and lesser tubercles of the horse's humerus; it serves to restrain the bicipital tendon.
• intervenous t. — a fold on the inner wall of the right atrium, directing the flow of blood from the venae cavae to the atrioventricular opening.
• miliary t. — one of the many minute tubercles formed in many organs in acute miliary tuberculosis.
• phallic t. — primordia of the penis; called also genital tubercle.
• pubic t. — a prominent tubercle at the lateral end of the pubic crest.
• supraglenoid t. — a tubercle on the scapula for attachment of the biceps muscle.

A small tuber; a pealike nodule on the roots of most legumes; a rounded knoblike outgrowth on the ridge or face of many cacti.

This view of the cactus Mammillaria marksiana shows its pattern of prominent tubercles, with the spines emanating from each tubercle's tip.

See also: tubercle (anatomy)

A tubercle is generally a wart-like projection, but it has slightly different meaning depending on which family of plants or animals it is used to refer to.

In the case of certain orchids and cacti, it denotes a round nodule, small eminence, or warty outgrowth found on the lip. They are also known as podaria, which is podarium in its plural form. When referring to some members of the pea family, it is used to refer to the wart-like excrescences that are found on the roots.

In mycology, a tubercle is used to refer to a mass of hyphae from which a mushroom is made.

When it is used in relation to certain dorid nudibranchs such as Peltodoris nobilis, it means the nodules on the dorsum of the animal.

Skin impression from the abdomen of the duck-billed dinosaur Edmontosaurus annectens, showing tubercular scales.

In dinosaurs, a tubercle is a general term for the scales seen in skin impressions. In duck-billed dinosaurs, for example, three main types of tubercles are defined: small tubercles with no definite arrangement (ground tubercles); larger, polygonal tubercles (pavement tubercles) up to 1 cm (0.4 in) in diameter, which are grouped into clusters separated by ground tubercles; and limpet-shaped conical scutes.^[1]

See also

• Glands of Montgomery

References

1. ^ Lull, Richard Swann; and Wright, Nelda E. (1942). Hadrosaurian Dinosaurs of North America. Geological Society of America Special Paper 40. Geological Society of America. pp. 111-112. 

External links

Tubercle at Cactus-Art.biz

This biology article is a stub. You can help Wikipedia by expanding it.

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)