========= ANNALS Of ANATOMY ========= Morphometric evaluation of paranasal sinuses for endoscopic sinus surgery H. Hali s Unlii*, Ibrahim Tekdemir**, Mehmet Ersoy**, Refik Caylan ", Kaplan Armcr'" and Yildmm Nalca" *Department of Otorhinolaryngology, Numune State Hospital, and **Department of Anatomy, Ankara University, Faculty of Medicine, Anatomi Bilim Dah, 06100, Sihluye, Ankara, Turkey Summary. Endoscop ic surgical treatment of paranasal sinus infections is currently being applied in many Otorhinolaryn- gology Clinics. Although high rates of success are reported with this treatment method, life threatening complications sometimes do occur due to disorientation, especially when angled telescopes are used. In order to avoid such compli- cations, we evaluated the distances from the anterior nasal spine to various important anatomic structures encountered during endoscopic surgery. The measurements obtained by a morphometric anatom ic study of cadavers are presented in this study. We believe that if surgery is carried beyond the measured distances, serious complications may ensue during endoscopic surgery. Key words: Nasal endoscopy - Sinus anatomy - Sinus surgery Introduction Endoscopic Sinus Surgery, introduced in the late seventies by Messerklinger and Wigand in the treatment of paranasal sinus infections, was popularized by the authors like Stamm- berger, Kennedy and Hosemann in the following years. This techn ique make s use of angled monocular telescopes trans- nasally, enabling surgery of the lateral nasal wall and ethmoidal cells (Fig. 1). With this technique, normal anatomic structures can be preser ved in patients with chronic/recurrent sinusitis and the obstructed ostia of the diseased major sinuses can be dilated in order to establish the normal ventilation of the sinuses (Kennedy 1985; Stammberger and Posawetz 1990). In literature, the reported rate of successful treatment of sinusitis by endoscopic Correspondence to: Kaplan ArmCI Ann Anat (1994) 176: 193-1 99 Gustav Fischer Verlag Jena Fig. I. In this figure the position of the patient in endoscopic sinus surgery is shown. The procedure is applied transnasally. ethmoidectomy varies from 85 to 98% (Wigand and Hose- mann 1991; Levine 1990; Rice 1989; Kamel 1989; Kloppers 1989).