A New Horizontal Plane of the Head

AIM: This study aimed to attempt to introduce a new extracranial horizontal plane of the head (K plane that extends from SN to SAE bilaterally) that could act as a substitute to the Frankfurt horizontal intracranial reference plane; both clinically and radiographically. MATERIAL AND METHODS: The new K plane depended on three points of the head. The first was the soft tissue nasion (NS) on the interpupillary line when the subject looked forward at a distant point at eye level. The other two points were the superior attachments of the ears (SAE). RESULTS: The student “t” test comparing mean values of K/V and FH/V was not significant; -0.21. The coefficient of correlation between different variables was highly positively significant (r = 0.98 with probability = 0.001). CONCLUSION: Within the limitations of this prospective study, the new K plane was found to be both reliable and reproducible. It can be used as a reliable reference plane instead of Frankfort horizontal plane both clinically and radiographically; as it is an accurate tool for head orientation in the natural head position.