Report of an anatomic study of the lateral cisternal punctures (at the atlanto-occipital and C1-2 interspaces), carried out on fresh cadavers. Direct visualization of the internal surface of the dura mater (DM) at the cranio-cervical junctions was possible by removing the calvarium and brain (sectioned at the upper cervical spinal cord). Dislocation («tenting») of the DM over the needle was observed in all occasions (n = 42), measuring 3.46 mm (2-6 mm).