VARIATIONS OF THE UNCINATE PROCESS OF THE LATERAL NASAL WALL WITH CLINICAL IMPLICATIONS

The morphology of the uncinate process (UP) and nasal fontanelle is de scribed in 119 human specimens, which were examined both before and af ter 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 conc ha (turbinate). This was the most frequently observed type. Subtype I- b: The UP adhered to the inferior concha along the antero-inferior mar gin. The anterior nasal fontanelle was closed by the UP adhesion; ther efore, 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 t o the superior structures, such as the bulla ethmoid, medial orbital w all, tegument of the maxillary sinus, and basal area of the ethmoid si nus. These structures are known as high-risk areas of endonasal surger y (Levine, 1993). Type P: The tip articulated with the perpendicular p late of the palatine bone. The UP was prolonged posteriorly. Attention should be paid to the sphenopalatine artery: which goes through the p osterior edge of the middle concha. Four additional variations (combin ations of the above basic types, Variations IS, IF, SP, and ISP) were also observed. Clin. Anat. 11:295-303, 1998. (C) 1998 Wiley-Liss, Inc.