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Objectives: The previously described S-point, corresponds to the medial projection of the middle turbinate axilla in the superior nasal septum and has been identified as a common source of severe epistaxis. The objective is to define the anatomical patterns of vascularization of the S-point area that could explain its clinical relevance., Methods: Thirty-three nasal septums of latex-injected formalin-embalmed and fresh human cadaveric heads were dissected to analyze the arterial arrangement of the S-point area. Measurements and patterns of vascularization were described., Results: The S-point area, was consistently surrounded by a single or multiple arterial anastomotic arches consistently formed superiorly by the anterior ethmoidal and posterior ethmoidal artery branches, and inferiorly by the posterior septal artery. The caliber of the arterial arches was typically larger than the caliber of the arterial branches supplying them. A single arch was present in 36.3% of septums, and multiple arches in 63.6%. The mean distance from the S-point to the anterior limit of the arch was 9 mm, to the posterior arch when the present was 3 mm, to the superior limit 6 mm, to the inferior limit 6 mm, and to the nasal roof was 10 mm., Conclusion: This study demonstrates the dense arterial configuration of the S point area, which is characterized by a single or multiple vascular arches of greater caliber than the branches of origin. This finding could explain why the S-point area is a frequent source of epistaxis, and guide its surgical cauterization when an obvious vascular ectasia is not visualized., Level of Evidence: N/A Laryngoscope, 133:2075-2080, 2023., (© 2022 The American Laryngological, Rhinological and Otological Society, Inc.)

Introduction  The endoscopic endonasal transpterygoid approach (EETPA) with or without the addition of the endoscopic-assisted sublabial anterior transmaxillary approach (ESTA) has become increasingly utilized for lesions posterior to the pterygopalatine fossa (PPF), including infratemporal fossa (ITF), lateral recess of the sphenoid sinus, Meckel's cave, petrous apex, and parapharyngeal space. The main goal of this study is to develop an educational resource to learn the steps of the EETPA for trainees. Methods  EETPA and ESTA were performed in 12 specimens by neurosurgery trainees, under supervision from the senior authors. One EETPA and one ESTA were performed on each specimen on opposite sides. Dissections were supplemented with representative cases. Results  After a wide unilateral sphenoidotomy, ethmoidectomy, and partial medial maxillectomy, the anteromedial bone limits of the PPF were identified and drilled out. The pterygoid progress was modularly removed. By enlarging the opening of the posterior and lateral walls of the maxillary sinus through EETPA and ESTA, respectively, the neurovascular and muscular compartments of the PPF and ITF were better identified. The EETPA opens direct corridors to the PPF, medial ITF, middle cranial fossa, cavernous sinus, Meckel's cave, petrous apex, and internal carotid artery. If a more lateral exposure of the ITF is needed, the ESTA is an appropriate addition. Conclusion  Despite the steep learning curve of the EETPA, granular knowledge of its surgical anatomy and basic surgical steps are vital for those advancing their learning in complex endoscopic approaches to the ventral skull base when expanding the approach laterally in the coronal plane., Competing Interests: Conflict of Interest None declared., (Thieme. All rights reserved.)