
Aim: The purpose of this study was to evaluate the correlation of the actual and effective symphysis with other craniofacial parameters to detect the direction of mandibular growth. Material and Methods: The sample for the study consisted of 120 patients (60 males and 60 females) with age of the subjects ranging from 18 to 30 years, having Class I skeletal and dental relations and full permanent dentition regardless the third molars. Two symphyseal measurements with eleven measurements for mandibular rotation were assessed using AutoCAD computer program. Statistical analysis: Descriptive statistics, Independent samples t-test and Pearson’s Correlation Coefficient were used to evaluate the correlation of the actual and effective symphysis with other craniofacial parameters, gender difference and the ethnic difference. Results: For both the genders and the total sample, the actual symphysis did not show any significant correlation with the facial heights and the mandibular rotation angles, whereas on the other hand, the effective symphysis showed significant positive correlations with Jarabak ratio and saddle angle, and significant negative correlations with SN-MP, PP-MP, FMA, and Sum of of posterior angles. Conclusion: Effective symphysis is a good predictor of the direction of mandibular rotation whereas the actual symphysis is a bad predictor. Also, actual symphysis exhibited ethnic differences when compared to the Iraqi population.