Tubercle

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 (singular podarium). 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. These tubercles in nudibranchs can present themselves in different ways: each tubercle in a single rounded, conical or angular form, each tubercle in a compound form of two or more levels, tubercles in amalgamated clusters or as tubercles forming or joined by a ridge.

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.

Tubercle (anatomy)

In anatomy, the term tubercle may describe a round nodule, small eminence, or warty outgrowth found on bones or skin, or, in cases of tuberculosis, in the lungs.

In addition to the types that exist in or on humans (as well as certain other animals) as described below, they are also found on the leading edge of Humpback Whale's flippers, improving fluid flow over the flipper's surface.

Types

Within the human body there are numerous sites where tubercles develop. On bones they are generally the sites of muscle insertions. Within the lungs and on the genitals, tubercles are sites of disease.

Mouth

Tubercles are usually found behind the last molar in the upper jaw, covered by the gum. Surgery can be done to make tubercles less prominent.

Arms

The humerus of the upper arm has two tubercles, the greater tubercle and the lesser tubercle. These are situated at the proximal end of the bone, that is the end that connects with the scapula. The greater/lesser tubercule are located from the top of the acromion laterally and inferiorly. The radius has two, the Radial tuberosity and Lister's tubercle.

Rib cage

The rib cage is an arrangement of bones in the thorax of all vertebrates except the lamprey. It is formed by the vertebral column, ribs, and sternum and encloses the heart and lungs. In humans, the rib cage, also known as the thoracic cage, is a bony and cartilaginous structure which surrounds the thoracic cavity and supports the pectoral girdle (shoulder girdle), forming a core portion of the human skeleton. A typical human rib cage consists of 24 ribs, the sternum (with xiphoid process), costal cartilages, and the 12 thoracic vertebrae. Together with the skin and associated fascia and muscles, the rib cage makes up the thoracic wall and provides attachments for the muscles of the neck, thorax, upper abdomen, and back.

Structure

Ribs are described based on their location and connection with the sternum. Ribs that articulate directly with the sternum are called true ribs, whereas those that connect indirectly via cartilage are termed false ribs.

Attachment

The terms true and false rib describe rib pairs that are directly or indirectly attached to the sternum. The phrase true rib (Latin: costae verae), or fixed rib, refers to the first seven, or vertebrosternal, rib pairs. The phrase false rib (Latin: costae spuriae), or vertebrochondral ribs refers to the eighth-to-twelfth pairs of ribs. The eighth-to-tenth pairs of ribs connect to the sternum indirectly via the costal cartilages of the ribs above them. Their elasticity allows ribcage movement for respiratory activity.