AskDefine | Define thorax

Dictionary Definition



1 the middle region of the body of an arthropod between the head and the abdomen
2 the part of the human body between the neck and the diaphragm or the corresponding part in other vertebrates [syn: chest, pectus]
3 part of an insect's body that bears the wings and legs [also: thoraces (pl)]

User Contributed Dictionary



From sc=Grek, from sc=Linb.


thorax (plural thoraces or thoraxes)
  1. the middle of three distinct divisions in an insect, crustacean or arachnid body
  2. the region of the mammalian body between the neck and abdomen as well as the cavity containing the heart and lungs


region of the mammalian body
  • Czech: hruď, hrudník
  • Greek: θώρακας

Extensive Definition

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 (as in the fly shown, where the metathoracic wings have been reduced to tiny balancing organs called halteres). 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.


thorax in Arabic: قفص صدري
thorax in Catalan: Tòrax
thorax in German: Thorax (Gliederfüßer)
thorax in Spanish: Tórax
thorax in Basque: Torax
thorax in French: Thorax
thorax in Indonesian: Thorax
thorax in Icelandic: Frambolur
thorax in Italian: Torace
thorax in Hebrew: בית החזה
thorax in Latin: Thorax
thorax in Lithuanian: Krūtinės ląsta
thorax in Simple English: Thorax
thorax in Polish: Tułów
thorax in Slovenian: Oprsje
thorax in Thai: อก
thorax in Turkish: Göğüs
thorax in Chinese: 胸部

Synonyms, Antonyms and Related Words

Privacy Policy, About Us, Terms and Conditions, Contact Us
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2
Material from Wikipedia, Wiktionary, Dict
Valid HTML 4.01 Strict, Valid CSS Level 2.1