Variations of the uncinate process of the lateral nasal wall with clinical implications

The morphology of the uncinate process (UP) and nasal fontanelle is described in 119 human specimens, which were examined both before and after removal of the mucosa. Forms of the UP are classified and based on which site the process is articulated, and each form is characterized in relation to the endonasal endoscopic operative technique. Type I: The infero-posterior tip of the UP is articulated to the inferior concha (turbinate). This was the most frequently observed type. Subtype I-b: The UP adhered to the inferior concha along the antero-inferior margin. The anterior nasal fontanelle was closed by the UP adhesion; therefore, special attention is required not to damage the lacrimal bone. Type N: The tip of the UP had no articulation and made a free edge. It reduces the bony resistance at surgery. Type S: The tip articulated to the superior structures, such as the bulla ethmoid, medial orbital wall, tegument of the maxillary sinus, and basal area of the ethmoid sinus. These structures are known as high-risk areas of endonasal surgery (Levine, 1993). Type P: The tip articulated with the perpendicular plate of the palatine bone. The UP was prolonged posteriorly. Attention should be paid to the sphenopalatine artery, which goes through the posterior edge of the middle concha. Four additional variations (combinations of the above basic types, Variations IS, IP, SP, and ISP) were also observed.