An anatomical study of the frontal sinus in 100 macerated skulls. The study introduces an innovation on the literature by means of the measurement of the sinus's volume. All the found information in the literature attained to other aspects including the diameters of the sinus and the geometric área of the same. Objective: Evaluation of the measures of the frontal sinus frequently involved in cranial base surgeries and supraorbital craniotomies in order to help the surgical approaches that cross this anatomical route Methods: The measurement included: sagital, transverse and an tero-posterior diameter acquired with a paquimeter and the volume obtained after filling the sinus with sand. Results: They are in accordance with the literature that shows the male's predominance in all measurements done.