The posterior groove as a landmark for location of the palatovaginal canal in axial computed tomography.

Abstract

To investigate use of posterior groove of palatovaginal (PV) canal as an anatomic landmark in determining the location of PV canal in axial computed tomography (CT) images of pterygopalatine fossa (PPF). A total of 20 skull specimens were examined in this analysis. Each skull was scanned by CT with and without a probe inserted through PV canal to measure the anatomic structures. CT images of 70 patients were used for comparing the rate of correct location of PV canal between the conventional method (using the vidian canal as a landmark) and the method of using the posterior groove as a landmark. Two skulls were dissected using endoscopy to further reveal the advantage of the posterior groove as a landmark. In all 20 skull specimens, the groove showed the morphology of a narrow groove and elliptical fossa in 24 and 16 sides, respectively. In CT images, the angle from PV canal and the posterior groove to the hard palate was 53.14°±5.48° and 20.93°±6.28°, respectively, which was significantly different (P≤0.05). The rate of correct location of PV canal was statistically significantly higher with the method of posterior groove as a landmark than the conventional method (70.7 vs 49.3%, P<0.05). The endoscopic anatomy of the posterior groove and its use in locating the PV canal were described. The posterior groove can be used as an anatomic landmark in correctly locating PV canal in the axial CT image of the PPF.