Anatomy and CT reconstruction of the anterior area of sphenoid sinus.

BACKGROUND The anatomical structures of anterior area of sphenoid sinus are observed by CT reconstruction of radiographic images in some studies. However, the detailed anatomic information of the extended transsphenoidal approach is still incomplete. METHOD Fifteen cases (30 sides) of adult cadaveric skulls and 20 cases (40 sides) of bleached adult dry skulls were observed and measured under microscope. CT imaging data were obtained from 12 patients. RESULTS Anatomy of anterior area of sphenoid sinus and sphenopalatine artery observed from CT three-dimensional reconstructed images was consistent with that observed from adult cadaveric skulls and bleached adult dry skulls. The anterior sphenoid sinus wall resembled a bird head, with midline protrude prismatically. The sphenoid ostia on both sides were in shape of bird-eyes, and the sphenoidal rostrum below was like the beak. The "shallowest point" was firstly reported in this study and was defined as the nearest point from the nostril to the anterior sphenoid sinus wall. It was located about 5.5 mm from sphenoid sinus ostium, and 5 mm from the upper edge of the posterior choanae. It was an important anatomical reference mark in locating the sphenoid sinus ostium in the anterior sinus wall. CONCLUSION The three-dimensional images reconstructed by CT scan can visually display the bone structure of anterior area of sphenoid sinus, sphenopalatine artery and its main branches. Virtual endoscopy reconstruction can confirm the structural details of CT reconstruction and simulate transsphenoidal surgery.