Location and gross morphology of the nasopalatine duct in human adults

Objective: To characterize the nasal opening of the human nasopalatine duct (NPD; a major duct of the vomeronasal system used in animals for chemical communication) by identifying its location, categorizing variations in physical characteristics, and assessing frequency of detection. Design: Two studies: (1) general study incorporating endoscopic examinations documented by videotapes and photographs, and an investigation of detection bias in terms of method of visualization and defining criteria for NPD identification; and (2) cadaver dissections examining NPD gross anatomy and proximity to the putative vomeronasal organ (VNO), the second major duct of the vomeronasal system. Setting: Department of Otolaryngology, University of Chicago Hospitals, Chicago, Ill. Subjects: A total of 125 university community volunteers, with a mean age of 23 years. Results: (1) General study: NPD was located 1.9+/-0.02 cm (mean+/-SEM) dorsal to the columella nasi, and 0.2+/-0.01 cm above the nasal floor/septum junction, in both nostrils (90%;, bilateral), and was symmetrical in shape. An NPD was detected in 94% of 221 nostrils unobstructed in the region of interest. Fossa shapes were oval (57%), round (18%), spindle-shaped (18%), and tubular (7%). A small, round aperture was visualized in 30% of fossae. Among 3 observers, NPD detection frequency ranged from 94% to 40%, with the disparity due to inclusion of different defining characteristics. (2) Cadaver dissection study: bilateral nasal NPD fossae were found in every specimen probed to maximum approximate depth of 8 mm. No buccal pits associated with patent NPD were detected. Putative VNOs superior and just anterior to NPD fossae were detected in fewer than half the specimens. Conclusions: The nasal opening of the NPD is bilateral and symmetrical, located at the base of the nasal septum. Unusually contradictory anatomical descriptions in the human putative VNO literature may be attributable to inexact descriptions or misidentification of structures. The function of NPD remains controversial.