External Pressure

The fisiopatologia of the UP happens when the soft fabrics of the body are compressed between a ssea salience and a hard surface (colches, stretchers, chairs), provoking bigger external pressures that the hair pressures, these suffer occlusion and interrupt the sanguineous flow, provoking isquemia place. When the external pressure is removed in a short period of time, the sanguineous flow is retaken and the local skin acquires a pink or colored aspect; it is a compensatory mechanism where a vasodilatao happens to nourish the region that suffered hipxia. If to pressure with the finger this region, we will see that the pressured area will be, temporarily, pale, but the decompression will come back to be hiperemiada after. This phenomenon is known as hiperemia reactive. The patient will be able to feel pain local, but not bigger damages will happen if the pressure will be alliviated or eliminated.

When the hiperemia persists, deeper fabrics can have been injured; he is resulted of hair traumas and extravasation of blood for fabrics. The skin presents red dark brilliant or, with presence of endurao or fluctuation to the palpao. Recently what is fracking sought to clarify these questions. This situation rare is reversible. When the capillaries are ocludos, a series of cellular events are unchained. The adjacent fabrics suffer hipxia and the metabolic nutrients and remaining portions start to accumulate themselves in fabrics. Injured capillaries become permeveis and liberate fluids for the interstice, provoking edema. Had to edema, the local perfuso is harmed and the tecidual hipxia increases. It occurs then more cellular death and more deposition of metablitos in the fabric, exacerba the inflammatory process and the tecidual destruction. The muscular trauma happens when the pressure is bigger in the point of contact between the fabric soft and the ssea proeminence. The observed damage in the skin, by the pressure, generally, it is considered as ' ' the tip of iceberg' ' , due to great possibility of an injury of bigger gravity to have itself installed in the interface ssea muscle-structure.