Radiographic and anatomic characterization of the nasal septal swell body.

OBJECTIVE To analyze the radiographic, anatomic, and histologic characteristics of the nasal septal swell body. DESIGN Computer-aided analysis of magnetic resonance images (MRIs) and histologic examination of cadaveric nasal septa. SETTING Tertiary medical center. PATIENTS Fifty-four head MRI studies were performed on adult live patients; we also used 10 cadaveric nasal septa. MAIN OUTCOME MEASURES Radiographic dimensions of the swell body and distances to other nasal landmarks were measured. Nasal septa and swell body histologic characteristics were evaluated using light microscopy. Relative proportions of vascular, connective, and glandular tissues within the swell body and the adjacent septum were compared. RESULTS The swell body was fusiform shaped and located anterior to the middle turbinate, with mean (SD) width of 12.4 (1.9) mm; height, 19.6 (3.2) mm; and length, 28.4 (3.5) mm. The epicenter was 24.8 (2.9) mm from the nasal floor, 43.9 (4.1) mm from the nasal tip, and 39.0 (4.6) mm from the sphenoid face. Histologic analyses revealed that, compared with adjacent septal mucosa, the swell body contained significantly more venous sinusoids (37% vs 16%, P < .001) and fewer glandular elements (28% vs 41%, P < .001). CONCLUSIONS The swell body is a conserved region of the septum located anterior to the middle turbinate approximately 2.5 cm above the nasal floor. The high proportion of venous sinusoids within the swell body suggests the capacity to alter nasal airflow. Additional study is required before these findings are used in a clinical setting.