Its bone architecture consists of 12 vertebrae, known as the dorsals, from which the right and left ribs start, ending in front at the sternum. There are 3 false ribs and 2 floating ribs on each side.

Its upper part is complemented by the clavicles and shoulder blades, where many muscles are inserted essential to the proper functioning of the shoulders (rotator hair)

Between these ribs are the intercosal muscles, which have a role in the inspiration and exhalation, but also at the postural level, since they allow the rotational movements of the trunk.

The diaphragm, on the other hand, is a skeletal muscle that has an open parachute shape, with a horizontal anterior part, and a vertical posterior.

It delivers from 3 holes to:

1)the aorta (unextensible fibre) at the height of D12, which then becomes the abdominal aorta to give the celiac trunk

2)The Lower Cave Vein at D9 Height

3)the esophagus

It is formed of 2 domes, the right being higher because of the liver, the left is connected to the stomach by the gastro-phrenic ligament.

It limits the pulmonary sphere (at the level of the parietal pleura) of the abdomen, and has essentially inspiratory properties (inspiration being in 2 phases, thoracic and abdominal). It ends on the lumbar spine and the last dorsal (D12) at the pillars, which are 2 tendon expansions, the right is more powerful, and ends lower (L4) than the left (L3).

They're going to:

• "pull" the diaphragm down to let air into the lungs back, its dysfunction can lead to disorders such as Chronic Obstructive Pulmonary Disease (COPD).

• Surround the esophagus in the manner of a lasso forward, its excessive contraction thus hindering the opening of the Eso-Gastric Junction (JOG), for the passage of food, and thus create a possible hiatal hernia, the origin of Gastroesophageal Reflux, with retro-stern burns, bad breath, dysphony, feeling of body

In the lower and posterior parts, we note the presence of the kidneys that are attached to the spine, between D11 and L3, and which are in a retro-peritoneal situation. The right is lower because of the liver.

A limitation of chest mobility is common, because, as we have seen, it is an area directly related to breathing, and that the contemporary way of life, at a frantic pace, with new technologies, the constraints of privacy, leads us to live "at a hundred per hour", and can have a real psychological impact, it is the psycho-somatic.

On the other hand, one can think that a psychological gateway (ill-being, tensions in family or professional private life, pressure from the employer with objectives difficult to achieve …) can interfere with breathing, and create physical tension on the diaphragm in particular. Thus, a physical gateway linked to a postural disorder (bad postures during the day, traumatic history that causes certain joints to "disartthis") can create stress, and pain: it is the somato-psychic.

This is why the Osteopath will pay special attention to this region, teaching the patient to breathe, through the stomach or chest, by bringing out his emotions if possible, and by scrupulously scrutinizing each rib and testing them for possible "blockages" (it can either be limited upwards in "superiority" or be limited down to "inferiority").

Indeed, it is this thoracic region that depends on the irrigation of the whole organism, by the presence of the heart, which can see its coronary arteries eventually clog. Preventive osteopathy can detect these tensions and prevent more serious disorders later on.

The heart lodges in the mediatin, and works like a pump that expels oxygenated blood (O2) from the lungs and sucks the CO2-laden blood from the great circulation.

Note that some structures do not need to be irrigated by the bloodstream to function, as is the case of cartilage, at the extreme of the bones, which is a so-called avascular structure, because it does not need blood to function and ensure its metabolism.

Indeed, its cells on the surface, the chondrocytes, feed by imbibition of the synovia by impregnating proteins such as Glycosaminoglycans. This in-depth nutrition is only permitted through joint mobility, so that overweight, sedentary living, modern working conditions, sitting for several hours, induce early cartilage wear, or osteoarthritis.

Traumatic history can also lead to osteoarthritis, often years later, because the joints that have compensated for a long time, no longer working in physiological axes, post-traumatic postural shifts have gradually settled, and have altered the "body pattern". Some areas of the cartilage have been hyperpressive, while others have not been able to absorb their synovia.

It is better then understood the interest of seeing an osteopath regularly in prevention, on average at least 3 times a year, some patients say they like to consult once a season.

Thus, we can say that osteopathy manipulations prevent the degenerative phenomena of osteoarthritis, although for most authors, cartilage erosion is linked to normal, physiological aging of the joint.

Thus, osteoarthritis alters the synovial fluid which becomes rarer, and of lower quality.

A neovascularization will eventually be created, as if cartilage were to "tap" into the nutrients of the blood, to carry local chemical mediators on an inflammatory outbreak, but also to eliminate metabolic waste.

This creates real "highways", a kind of arteriovenous micro-network, for the deposition of proteins of inflammation, such as growth factors (TGF), cytokines, interleukins, prostaglandins… for the diapesis allowing their hair release.

Edema, or effusion, which causes pain at night or even in the morning, can manifest itself, stiffness is also a frequent sign.

Radiological signs are also evocative, allowing us to know the stage of osteoarthritis with subchondrale deficiencies (geodes), a pinch of the interline (with osteocondensations or "white edict"), bone deformities (osteophytes, or "parrot beaks") …

Note that other structures are also avascular, such as the central part of the intervertebral discs, the inner part of the meniscus of the knees….