Objectives: Fossa pterygopalatina is located posterior to maxillary sinus, anterior to pterygoid plates and inferior to greatersphenoid wing. Tumors that arise in fossa pterygopalatina are usually asymptomatic and often discovered at late stage.Because of its deep and relative inaccessible location, clinical examination of fossa pterygopalatina is difficult. Aplastic ornonvisible foramen rotundum may give an early indication for the regional tumors.Methods: In the present study, foramen rotundum was visualized as a round structure with prominent sclerotic margins located near ethmoid cells, maxillary sinus or orbital cavity in X ray images. X-rays (radiographs) of 17 dry skulls and 7 half dry skullswere performed with Phillips Digital Diagnost X-Ray device. All dry skulls were positioned similar to Caldwell’s view. We havedesigned a fixation apparatus to optimize the positioning of dry skulls and half skulls. After fixation of the skulls with the apparatus, the X-ray beam centered about 3–4 cm below the external occipital protuberance with an angle of 15 degrees to thechantomeatal line. Each radiologic image was examined for the location of foramen rotundum in relation with orbital cavity, ethmoidal cells and maxillary sinuses. We described the characteristic of foramen rotundum with count and percent values.Results: In the present study, 41 foramina rotunda were analyzed. Out of 41 foramina rotunda, twenty were right-sided, twenty one were left-sided. Of the 20 right-sided foramina rotunda, 19 were visible on X-ray images. On the other side 18 of 21 leftsided foramina rotunda were apparent. 14 of 19 visible right-sided foramina rotunda were identified in the orbital cavity(73.68%). Three of them were identified in ethmoidal cells, and two in the maxillary sinus. 11 of 18 visible left-sided foraminarotunda were identified in the orbital cavity (61.11%). Two of these were found in ethmoidal cells, eight in the maxillary sinus.Out of 17 dry skulls, one had bilateral nonvisible foramina rotunda.Conclusion: Foramen rotundum must be taken into consideration in evaluation of routine X-rays to prevent misdiagnosis ofthe patients with persistent non-specific symptoms.