Thorax

The thorax is the upper part of the body between the neck and abdomen. It consists of a bony cage made up of the sternum, ribs, and vertebrae of the thoracic spine. This skeletal cage protects the internal organs and participates in breathing.

Inside the thorax are the lungs on both sides and in the middle a space called the mediastinum, which contains the heart, major blood vessels, the esophagus, and the trachea. The thorax and abdomen are separated by the diaphragm, the most important muscle for breathing.

Structure of the bones

The ribs originate from the spine and curve forward. Most are attached to the sternum by cartilage. Some of the lower ribs do not reach the sternum and end freely. The joints between the bones and cartilage give the thorax flexibility, allowing it to expand and contract during breathing.

Breathing

When air is inhaled, the diaphragm moves downward, the intercostal muscles lift the ribs upward, and the volume inside the thorax increases. This decrease in pressure draws air into the lungs. When air is exhaled, the muscles relax and the thorax decreases in size.

The heart and circulation

The heart lies in the center of the thorax, tilted slightly to the left. It pumps oxygen-poor blood to the lungs, where it is oxygenated, then pumps oxygen-rich blood to the rest of the body. Major vessels such as the aorta and esophagus pass through the thorax on their way to other parts of the body.

Terminology and medical use

In Somali, the word laab refers to the upper front part of the body and is sometimes used figuratively (for example, laab furan, open chest). Chest pain is considered an important symptom related to the heart, lungs, esophagus, or muscles. Routine examination includes listening to breathing and the heartbeat, chest X-rays, and measurement of heart electrical activity.