The effect of age on the anteroposterior (A-P) position of the mandibular foramen (MF) and on the size of the gonial angle (GA) was evaluated in this study. From an Israeli Bedouin population, 121 dry mandibles with primary (36), mixed (26), and permanent dentitions (59) were analyzed. The A-P position of the MF perpendicular to the posterior border of the ramus was measured with a digital caliper. A mandibulometer was used to evaluate the GA. The MF distance from the posterior border of the ramus increased significantly with age by 66% from primary (7.75 mm) to permanent (12.9 mm; P < 0.001). Similarly, the MF distance from the posterior border of the ramus relative to the total ramus width in A-P dimension increased significantly (21.4%) with altered dentitions from primary (0.28) to late permanent dentition (0.34; P < 0.001). The GA decreased significantly with age from 140.17 AE 5.9 (primary dentition) to 123.61 AE 6.9 (late permanent dentition; P < 0.001). The anterior movement of the MF and the decreased size of the GA that occurred with changing dentition were related to growth process. The MF moves anteriorly, and the GA decreases with age. Anat Rec, 294:1319Rec, 294: -1325Rec, 294: , 2011. V V C 2011 Wiley-Liss, Inc.Key words: gonial angle; children; mandibular block; scalp; horizontalThe most routinely used procedure for anesthetizing mandibular molars is the inferior alveolar nerve block (mandibular block), with a success rate of only 63%-87% (Kaufman et al., 1984;Childers et al., 1996). To increase the effectiveness of the mandibular block, the local anesthetic solution should be injected as close as possible to the mandibular foramen (MF). It is agreed that the MF moves superiorly with age. At 4-5 years, the MF is located under the occlusal plane; at 6 years, it is located at the level of the occlusal plane or slightly above; and it moves superiorly above the occlusal plane by 13 years (Lampshire, 1947; Shiere, 1950;Olsen, 1956;O'mullane, This research was conducted in partial fulfillment for a DMD thesis,