thorax

1. The part of the human body between the neck and the diaphragm, partially encased by the ribs and containing the heart and lungs; the chest.
2. A part in other vertebrates that corresponds to the human thorax.
3. The second or middle region of the body of an arthropod, between the head and the abdomen, in insects bearing the true legs and wings.

[Middle English, from Latin thōrāx, breastplate, chest, from Greek.]

The chest; the portion of the body trunk above the diaphragm and below the neck that contains the heart and lungs, and is enclosed by the thoracic cage.

The part of the body between the neck and diaphragm; the chest.

The part of the body between the neck and abdomen; the chest. It is separated from the abdomen by the diaphragm. The walls of the thorax are formed by pairs of ribs, attached to the sides of the spine and curving toward the sternum. The cranial pairs of ribs are attached to the sternum, the next few connect with cartilage connected to the sternum and often the last one or two (the floating ribs) are unattached distally. The cavity of the thorax is divided by a thick partition, the mediastinum. The principal organs in the thoracic cavity are the heart with its major blood vessels, and the lungs with the bronchi. The trachea enters the thorax to connect with the lungs, and the esophagus travels through it to connect with the stomach caudal to the diaphragm. See also thoracic.

This article mainly refers to animal anatomy. See Chest for the human anatomy article.

For other uses, see Thorax (disambiguation).

The thorax is a division of an animal's body that lies between the head and the abdomen.

In mammals, the thorax is the region of the body formed by the sternum, the thoracic vertebrae and the ribs. It extends from the neck to the diaphragm, and does not include the upper limbs. The heart and the lungs reside in the thoracic cavity, as well as many blood vessels. The inner organs are protected by the rib cage and the sternum.

In insects and the extinct trilobites, the thorax is one of the three main divisions (or tagmata) of the creature's body, each of which is in turn composed of multiple segments. It is the area where the wings and legs attach in insects, or an area of multiple articulating plates in trilobites. In most insects, the thorax itself is composed of three segments; the prothorax, the mesothorax, and the metathorax. In extant insects, the prothorax never has wings, though legs are always present in adults; wings (when present) are restricted to at least the mesothorax, and typically also the metathorax, though the wings may be reduced or modified on either or both segments. In the Apocritan Hymenoptera, the first abdominal segment is fused to the metathorax, where it forms a structure known as the propodeum. Accordingly, in these insects, the functional thorax is composed of four segments, and is therefore typically called the mesosoma to distinguish it from the "thorax" of other insects.

Each thoracic segment in an insect is further subdivided into various parts, the most significant of which are the dorsal portion (the notum), the lateral portion (the pleuron; one on each side), and the ventral portion (the sternum). In some insects, each of these parts is composed of one to several independent exoskeletal plates with membrane between them (called sclerites), though in many cases the sclerites are fused to various degrees.

The trilobite body is divided into three major sections, a cephalon with eyes, mouthparts and sensory organs such as antennae, a thorax of multiple similar segments (that in some species allowed them to roll up into a ball), and a pygidium, or tail section.

References

• Sam Gon III. "A guide to the Orders of Trilobites". http://www.trilobites.info/index.htm. Retrieved August 23, 2005. 

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

Dansk (Danish)
n. - brystkasse, bryst

Nederlands (Dutch)
borstkas, borststuk (van insect)

Français (French)
n. - thorax

Deutsch (German)
n. - Brustkorb, Thorax

Ελληνική (Greek)
n. - (ανατ.) θώρακας

Italiano (Italian)
torace

Português (Portuguese)
n. - tórax (m)

Русский (Russian)
грудная клетка, торакс

Español (Spanish)
n. - tórax

Svenska (Swedish)
n. - thorax, bröstkorg (anat.)

中文（简体）(Chinese (Simplified))
胸, 胸部, 胸廓, 胸甲

中文（繁體）(Chinese (Traditional))
n. - 胸, 胸部, 胸廓, 胸甲

한국어 (Korean)
n. - 흉부, 흉곽, 가슴 받이

日本語 (Japanese)
n. - 胸, 胸部

العربيه (Arabic)
‏(الاسم) الزور, الصدر‏

עברית (Hebrew)
n. - ‮חזה‬

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