Report of a study of the dynamic anatomy of the median suboccipital puncture of the cisterna magna cerebellomedullaris, carried out on fresh cadavers. Direct inspection of the internal surface of the dura mater (DM) at the craniocervical region was possible by removing the calvarium and brain (seccioned at the upper cervical cord), during routine necropsies. Dislocation of the DM over the needle tip preceding dural penetration (so-called «durai tenting») was observed in all punctures (n = 30), measuring 3.12 (2.0-4.2) mm.