Decubitus - an ischemic necrosis and a ulceration of tissues above an osteal prominence, it is long exposed to continuous pressure from the outside. Decubituses are formed more often at the lowered painful sensitivity on a background of an attrition, a paralysis (for example, in connection with damage of a spinal cord or degenerate neurologic diseases), at a long confinement to bed. The area of scapulas, a sacrum, ischiums, greater trochanters of femurs are especially subject to decubituses of a tissue of occipital area, etc.

Etiology. To the internal factors promoting development of decubituses, loss of painful sensitivity and perception of pressure (which induce the patient to change position of a body or to eliminate a source of pressure) concern. An atrophy in connection with the rare movement, the insufficient delivery, an anemia and infections too play a part. In the paralysed extremity loss of a vasculomotor regulation conducts to a vasodepression and rate of a blood flow that worsens conditions of microcirculation. A long hypotension also worsen microcirculation. From external factors most important pressure. At loss of mobility constant influence of pressure in some hours can already cause local disturbance of a circulation and a hypoxia of tissues which at absence of elimination lead to a necrosis of a skin and a subject tissues. Humidity owing to a diaphoresis, conducts incontiences of urine or a feces to a maceration of a skin and contributes to formation of decubituses.

Signs, current. At the first stage the erubescence which at pressing turns pale is marked or disappears. The second stage is characterized by a hyperemia, puffiness and a thickening of a skin; epidermal bubbles with the subsequent desquamation of a false skin are sometimes formed. In the third stage the necrosis begins, the exudation amplifies. In the fourth stage the necrosis reaches a muscular tissue. Advance of depth of a necrosis leads to destruction of bones, development of an osteomyelitis, a septic arthritis.