[Dynamics and pathogenesis of traumatic subdural hygroma].

Of 2005 patients, who had suffered blunt skull trauma, 108 developed post-traumatic subdural hygromas (TSH). CT was used to observe the course of subdural hygromas not treated surgically, with particular reference to the time of their appearance and regression. The relative incidence of TSH, and of the severity of head trauma quantified on a 5-grade scale was determined in different age groups. From the traumatic changes demonstrated on CT, some conclusions could be drawn regarding the pathogenesis. A hypothetical model has been developed which explains TSH as a result of shearing forces.