The intumescentia septi nasi anterior is a protuberance on each side of the anterior part of the nasal septum containing "cavernous" tissue. None of the previous studies devoted to the general aspects of endonasal "cavernous" tissue refer to the incidence and rhinological function of the intumescentia. This investigation revealed an incidence of more than 80% in 170 individuals without any rhinological symptoms. The external morphology observed in 7 cadavers indicated a close topographical correlation of the position of the middle turbinate, the depth of the lateral nasal wall and the extension of the intumescentia. Histological examination showed a glandular mass interspersed with a dense vascular network similar to the "cavernous" tissue found within the lateral turbinates. Various filling conditions of the intumescentia have no significant influence on rhinomanometrical parameters and the quantity of nasal airflow. However, visualization of the endonasal flow within a nasal model containing the septal protuberance indicated that the intumescentia considerably alters the quality and local velocities of the endonasal airstream. Considering the results of the study, the intumescentia must be regarded as a completely normal formation of particular rhinophysiological importance, which, up until now, has not been mentioned in rhinosurgery.