We report two cases of head trauma in which we observed a rapid disappearance of an acute subdural haematoma, in one case by means of control cranial CT scan, and in the other at explorative craniotomy. Mechanisms of this occurrence may be led to two main hypotheses: in the first a dilution and dispersion of the acute traumatic subdural haematoma (ATSH) in the CSF and subarachnoid spaces is supposed; in the second the ATSH is compressed by the brain swelling pressure and then redistributed.
