Cross-striated muscular tissue in white rats was studied histologically and morphometrically after the effect of
laser. In the first series of the experiment (25 rats) the tongue, musculus masseter and femoral muscles were cut by means of
carbon dioxide laser device "Scalpel-1" changing its power within the limits of 20, 40, 60, 80, 100% from maximum (35V). Immediately after the procedure, the pathological focus along the line of the incision had clear borders and consisted of a line of coagulated
necrosis and a zone of
necrobiosis. Its size was 48-75 mkm and depended on the power of irradiation and on how the
laser ray was directed towards the course of muscular fibres. A definite difference was revealed in the size of zones of coagulated
necrosis and
necrobiosis of lingual myons situating lengthwise and across the axis of the
laser ray. In the second series of the experiments (50 rats) regeneration of the tongue and musculus masseter was studied. On the first day,
edema and infiltration were insignificant because of coagulation of the blood vessels. Capillaries with the diameter of 20 mkm were forming from the preserved vessels and growing into the granulation tissue. On the second week, young muscular elements appear in the regenerate. Nonresorbted areas of the coagulated tissue impede myonic regeneration. On the 35-40 th day, fine muscular fibres, connective tissue and capillaires of normal size can be found within the traumatic area. The data obtained are compared with the results on reactivity of skeletal muscles after other types of lesions.