In 1987, Yoshino et al. proposed a system of classification of the frontal sinuses based on the following morphological characteristics: area size, bilateral asymmetry, superiority of area size, outline of superior borders, partial septa, and supraorbital cells. The current study confirmed the importance of Yoshino's identification system, examined possible errors in comparisons between antemortem and postmortem x rays, and proposed potential corrections. The probability of misclassification was also estimated. The study analyzed radiographic images of the skulls of 98 Italians (41 women and 57 men) between the ages of 17 and 98. X rays were digitalized and images were recorded in a computer file. Radiographic images of frontal sinuses were processed with a computer-aided drafting program. The x rays were used to evaluate frontal sinus areas according to Yoshino's classification system. In an attempt to improve the performance of Yoshino's method for identification of unknown skeletal remains, the study subsequently considered a new system of classification of the frontal sinuses based on the following morphological characteristics: SOR1 and SOR2, instead of the area size and bilateral asymmetry of Yoshino's method, along with superiority of area size, outline of superior borders, partial septa, and supraorbital cells. In addition, in order to examine the influence of skull position on the measured morphological variables, four skulls were analyzed in six positions. The study confirmed the usefulness of frontal sinus patterns in the identification of skeletal remains, and the adjustments to Yoshino's method significantly decreased the probability of misidentification. 7 tables and 16 references