2026 Poster Presentations
P455: ROADMAP TO THE INFRATEMPORAL AND PTERYGOPALATINE FOSSAE THROUGH ENDOSCOPIC ENDONASAL PERSPECTIVES: SURGICAL ANATOMY AND CLINICAL RELEVANCE
A. Yohan Alexander1,2,3; Rosaria V Abbritti, MD1,2,4; Luciano Leonel, PhD1,2,5; Jacob Eide1,6; Maria Peris-Celda MD, PhD1,2,5,6; 1Rhoton Neurosurgery and Otolaryngology Surgical Anatomy Program, Mayo Clinic, Rochester, MN; 2Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA; 3Medical School, University of Minnesota, Minneapolis, MN, USA; 4Department of Neurosurgery, Lariboisière Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France; 5Department of Clinical Anatomy, Mayo Clinic, Rochester, MN, USA; 6Department of Otorhinolaryngology, Mayo Clinic, Rochester, MN, USA
Introduction: Surgical anatomy of the infratemporal and pterygopalatine fossae is challenging for students of skull base surgery. To simplify understanding of the infratemporal and pterygopalatine fossae, we provide a resource describing its surgical anatomy, constant surgically relevant relationships, and techniques to identify key structures.
Methods: On eight sides of four embalmed, latex injected specimens, endoscopic endonasal sphenoidotomies and medial maxillectomies were performed. The posterior wall of the maxillary sinus was removed in all specimens studied while preserving the periosteum over the anterior surface of the pterygopalatine and infratemporal fossae. Muscular, nervous, and arterial structures were studied. Muscular structures studied were the lateral pterygoid and temporalis muslces. Nervous structures studied included the maxillary (V2) and mandibular (V3) divisions of the trigeminal nerve. Arterial structures studied included the maxillary artery and its branches.
Results: Regarding neural anatomy several consistent landmarks are identified once the medial maxillectomy and sphenoidotomy are completed. In all maxillary sinuses, the infraorbital nerve, accompanied by the infraorbital artery are clearly visible at the superolateral border. The infraorbital nerve, as it is a terminal branch of V2, can be followed posteromedially until the junction of the sphenoid and maxillary sinuses where V2 exits foramen rotundum – supplying fibers to the pterygopalatine ganglion. Additionally, in well pneumatized sphenoid sinuses, V2 can be identified by finding and unroofing foramen rotundum at the superior border of the lateral recess of the sphenoid sinus. To find V3, several strategies may be employed. First, if drilling of the medial middle fossa is necessitated, V2 can be followed posterosuperiorly towards Meckel’s cave, which can be followed inferiorly to V3. If the pterygopalatine fossa contents are entered or mobilized laterally, the buccal nerve, a branch of V3, can be identified and followed posteriorly towards foramen ovale. If none of these measures are required, V3 can be found by following the superolateral portion of the base of the pterygoid in a subperiosteal plane to identify foramen ovale, and, consequently, V3. Regarding arterial structures, several branches of the maxillary artery are identified after the sphenoidotomy and maxillectomy. Specifically, the infraorbital artery can be identified running with the infraorbital nerve, and the sphenopalatine artery can be identified at the junction of the sphenoid and maxillary sinuses; these can be followed medially and laterally, respectively to identify the maxillary artery in the middle of the pterygopalatine ganglion. The maxillary artery is always found running between the superior and inferior heads of the lateral pterygoid muscle. Regarding muscular structures, the three parts of the temporalis muscle are always identified readily at the lateral aspect of the infratemporal fossa after the periosteum behind the lateral posterior wall of the maxillary sinus is removed. The superior and inferior heads of the lateral pterygoid muscle are identified once the pterygopalatine fossa contents are lateralized or dissected. A cadaveric dissection video detailing anatomy and practical tips to identify key structures is also provided.
Conclusion: Through illustrative dissections, we present a practical guide to aid in understanding the surgical anatomy of the infratemporal and pterygopalatine fossae.
