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body division found in certain animals. In humans and other mammals it lies between the neck and abdomen and is also called the chest. The skeletal frame of the thorax is formed by the sternum (breastbone) and ribs in front and the dorsal vertebrae in back. Within the thoracic cavity are the heart, lungs, and esophagus. The chest and abdominal cavities are separated by a muscular structure, the diaphragm. In insects and other arthropods the thorax is a body division consisting of several segments lying between the head and abdomen, to which are attached legs or other appendages.



the upper (in humans) or anterior (in most vertebrates) part of the trunk.

The shape of the thorax is determined by its skeleton—the chest and pectoral girdle—and by the muscles arranged on its surface. In arthropods the thorax is the section between the head and the abdomen. In primitive crustaceans (for example, Phyllopoda) the segments of the thorax are numerous and not constant in number; they bear nonspecialized appendages, equipped simultaneously for swimming, chewing, and breathing (gills). In higher crustaceans the number of segments of the thorax is reduced to between four and eight and becomes constant; part of the segments fuse with the head and their appendages become maxillipedary. In Arachnida and Xiphosura the segments of the thorax bear four pairs of gressorial legs and are usually merged with the head into a cephalothorax. In insects the thorax consists of three segments (prothorax, mesothorax, and metathorax), to each of which is attached a pair of legs; in higher insects one pair of wings each is attached to the mesothorax and metathorax in the adult stage.


The chest; the cavity of the mammalian body between the neck and the diaphragm, containing the heart, lungs, and mediastinal structures. Also known as thoracic cavity.
(invertebrate zoology)
The middle of three principal divisions of the body of certain classes of arthropods.


1. the part of the human body enclosed by the ribs
2. the corresponding part in other vertebrates
3. the part of an insect's body between the head and abdomen, which bears the wings and legs
References in periodicals archive ?
Development and bursting of these blebs are linked to a higher transpulmonary pressure (alveolar pressure minus pleural pressure) in the apex of the thorax.
Thorax black with gray pollen except postalar callus, pteropleuron mostly and postero-upper corner of mesopleuron brownish yellow.
The bumblebee has a brown thorax, a dark abdomen and a white tip
The thorax houses structures such as lungs, heart and ribs, so when there is injury, trauma, pregnancy, surgery or dysfunction to the region, it can impair the rest of the body, namely the abdomen and pelvis.
Suggested ratios in birds are the proventricular diameter to keel height, the width of the cardiac silhouette to the width of the thorax, and the width of the cardiac silhouette to the width of the coracoid bone.
A 22 year-old female patient presented with septic pulmonary embolism (SPE) due to infective arthritis with demonstrative thorax CT images that provided early diagnosis and showed the evolution of radiological lesions.
The heart is one of a number of the popular 'plastinated' specimens the medical school has, along with a complete arm from shoulder to hand and a thorax including lungs and rib cage.
And they transmit force through a spring in their thorax.
It features driver and front passenger airbags, head and thorax airbags and ESP, with a trailer stabilisation system.
The one with the thorax had to be sent to another facility, and the one with the abdominal injury was treated here," he said.
SALAH AL-DIN / Aswat al-Iraq: A team of surgeons at the Tikrit Teaching Hospital on Saturday separated conjoined twins fused at the thorax, diaphragm, heart and liver in a landmark operation considered the first ever in Iraq, a medic said.