Endoscopic Anatomy of the Zygomatic Nerve: Implications for the Endoscopic Transmaxillary Approach.

 Understanding the anatomic features of the zygomatic nerve is critical for performing the endoscopic transmaxillary approach properly. Injury to the zygomatic nerve can result in facial numbness and corneal problems.  To evaluate the surgical anatomy of the zygomatic nerve and its segments from an endoscopic endonasal perspective for clinical implications of performing the endoscopic transmaxillary approach.  The origin, course, length, and segments of the zygomatic nerve were studied in four specimens from an endonasal perspective.  The zygomatic nerve arises 4.1 ± 1.7 mm from the foramen rotundum of the maxillary nerve in the superolateral pterygopalatine fossa (PPF). According to its anatomic region in endonasal endoscopic surgery, we divided the zygomatic nerve into two segments: the PPF segment, from origin to the point of entry under Muller's muscle, which runs superolaterally to the inferior orbital fissure (IOF) (length, 4.6 ± 1.3 mm), and the IOF segment, starting at the entry point in Muller's muscle and terminating at the exit point in the IOF, which travels between Muller's muscle and the great wing of the sphenoid bone (length, 19.6 ± 3.6 mm). In the transmaxillary approach, the zygomatic nerve is a critical landmark in the superolateral PPF.  The zygomatic nerve travels in the PPF and the IOF; better visualization and preservation of this nerve during endonasal endoscopic surgery are crucial for successful outcomes.