This study concerns four cases of sinus pericranii observed at the Neurological Department of Nancy. Sinus pericranii is a direct communication between the outer surface of the skull and the intracranial venous sinuses. It may be congenital, acquired or traumatic. This abnormality, usually located in the midline and often in the frontal region, is usually symptomless, but some patients complain of headache, nausea and vertigo. Sinus pericranii shows as a fluctuating non pulsatile mass of reddish or bluish colour, expanding when the patient bends his head down. Radiography usually shows one or several bone defects opposite the lesion found at CT bone window. On soft tissue window the mass is not calcified and usually enhanced by contrast injection. It is sometimes possible to visualize the vascular communication between the extracranial region and the underlying dural sinus. When visualization is blurred, or CT shows intracerebral abnormalities, MRI examination is required. Angiography with subtraction in venous phase (40 to 60 seconds after the injection), sometimes aided by films taken in head down position. It is of interest only in cases where CT and MRI have shown associated vascular abnormalities. Otherwise, direct injection of contrast medium into the malformation makes it possible to assert the diagnosis of sinus pericranii and to determine the flow rate within the malformation, which to some extent commands the the therapeutic technique. In patients with small and asymptomatic sinus pericranii absention is the rule. When the sinus is of moderate size, and the flow rate not rapid and when there is no significant communication with the cerebral veins, endovascular sclerosis may be advocated. In all other cases, surgical removal is recommended and is usually easy.