Purpose: The aim of this study is the identification of posterior nasal spine (PNS) for assessment of horizontal maxillary rotation. Materials and Methods: Five dry skulls were submitted for submentovertix cephalometric radiographs. Dental impressions were taken for the maxillae of these dry skulls and maxillary models were poured in extra hard stone. Data derived from cephalometric analysis were used for drawing reference line & points on the maxillary models. Finally, these maxillary models were compared with their corresponding actual maxillae f the dry skulls to determine the accuracy of the PNS identification and the possibility of midline deviation. Results: Two cases showed shift of maxilla to the left. One case showed midline deviation to the right. The remaining two cases showed identical palatal plane and skeletal midline which means that he maxilla is in the right relation to the rest of the skull. Conclusion: Identification of the PNS and adjusting midline deviation of maxilla will perfect and enrich model surgery procedures.