| Thoracic wall | |
|---|---|
 Body cavities | |
 A transverse section of the thorax, showing the contents of the middle and the posterior mediastinum. | |
| Identifiers | |
| MeSH | D035441 |
| FMA | 10428 |
| Anatomical terminology | |
Thethoracic wall orchest wall is the boundary of thethoracic cavity.
Thebonyskeletal part of the thoracic wall is therib cage, and the rest is made up ofmuscle,skin, andfasciae.
The chest wall has 10 layers, namely (from superficial to deep)skin (epidermis anddermis),superficial fascia,deep fascia and the invested extrinsic muscles (from theupper limbs), intrinsic muscles associated with theribs (three layers ofintercostal muscles),endothoracic fascia andparietal pleura. However, the extrinsic muscular layers vary according to the region of the chest wall. For example, the front and back sides may include attachments of largeupper limb muscles likepectoralis major orlatissimus dorsi, while the sides only haveserratus anterior.The thoracic wall consists of a bony framework that is held together by twelve thoracic vertebrae posteriorly which give rise to ribs that encircle the lateral and anterior thoracic cavity. The first nine ribs curve around the lateral thoracic wall and connect to the manubrium and sternum.[1]
When not breathing for long and dangerous periods of time in cold water, a person's body undergoes great temporary changes to try to prevent death. It achieves this through the activation of themammalian diving reflex, which has three main properties. Other thanbradycardia and peripheral vasoconstriction, there is a blood shift which occurs only during very deep dives that affects the thoracic cavity (a chamber of the body protected by thethoracic wall). When this happens, organ and circulatory walls allow plasma/water to pass freely throughout the thoracic cavity, so its pressure stays constant and the organs are not crushed. In this stage, the lungs' alveoli fill up with blood plasma, which is reabsorbed when the organism leaves the pressurized environment. This stage of the diving reflex has been observed in humans (such as world champion free-diverMartin Štěpánek) during extremely deep (over 90 metres or 300 ft) free dives.
In rare cases, intentional or accidental, trauma may lead to chest wall (thoracic wall) necrosis.[2]