: thoraces or thoraxes)[1] or chest is a part of the anatomy of mammals and other tetrapod animals located between the neck and the abdomen.

[2][3] In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the body, each in turn composed of multiple segments.

It contains organs including the heart, lungs, and thymus gland, as well as muscles and various other internal structures.

[5] In humans and other hominids, the thorax is the chest region of the body between the neck and the abdomen, along with its internal organs and other contents.

Arteries and veins are also contained – (aorta, superior vena cava, inferior vena cava and the pulmonary artery); bones (the shoulder socket containing the upper part of the humerus, the scapula, sternum, thoracic portion of the spine, collarbone, and the rib cage and floating ribs).

In the middle line the suprasternal notch is seen above, while about three fingers' breadth below it a transverse ridge can be felt, which is known as the sternal angle and this marks the junction between the manubrium and body of the sternum.

At the lower part of the sternum, where the seventh or last true ribs join it, the ensiform cartilage begins, and above this there is often a depression known as the pit of the stomach.

The nipple in the male is situated in front of the fourth rib or a little below; vertically it lies a little external to a line drawn down from the middle of the clavicle; in the female it is not so constant.

A little below it the lower limit of the great pectoral muscle is seen running upward and outward to the axilla; in the female this is obscured by the breast, which extends from the second to the sixth rib vertically and from the edge of the sternum to the mid-axillary line laterally.

[7] The major pathophysiologies encountered in blunt chest trauma involve derangements in the flow of air, blood, or both in combination.

Direct lung injuries, such as pulmonary contusions (see the image below), are frequently associated with major chest trauma and may impair ventilation by a similar mechanism.

If a heart attack occurs, the bulk of the damage is caused during the first six hours, so getting the proper treatment as quickly as possible is important.

Persons who add exercise to their daily routine generally feel this type of pain at the beginning.

When bronchial tubes are blocked, this condition develops and causes patients to feel shortness of breath.

The blockage may be caused by something inside the bronchus, such as a plug of mucus, a tumour, or an inhaled foreign object such as a coin, piece of food, or a toy.

[10] The size of the pneumothorax changes as air or gas builds up, so a medical procedure can release the pressure with a needle.

In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the creature's body, each of which is in turn composed of multiple segments.