The diameter of the abdominal aorta (AA), is a relevant factor to repair an abdominal aortic aneurysm. The aim of this study is to determine the normal range of the diameter of the infrarenal AA according 2D ultrasonography in patients with no history of vascular disease. Cross-sectional study, conducted in Hospital Regional of Temuco and Pitrufquen in 399 subjects over 15 years, with no history of vascular disease, who consulted for abdominal pain cadres were studied. 2D ultrasonography was performed with two different computers (General Electric RT3200 Advantage II and co Medison. Ltda. Model SA-600, both with 3.5 MHz transducers.) and two independent observers. The outcome variables were anteroposterior diameters (DAP) and transverse (TD) of AA. Other variables of interest were: sex, age index weight / height and body surface. Descriptive statistics were applied, applying inferential t test for continuous variables, x2 for categorical variables and Kruskal Wallis ANOVA for comparison of groups; correlation studies and linear regression. DAP average was 16.1 ± 2.2 mm (9-23 mm) and DT average was 19.4 ± 2.7 mm (11-26 mm). DAP and DT was significantly higher in the subgroup age > 50 and in men. There was a positive correlation between weight / height-DAP (p=0.0321) and index weight / height-DT (p=0.0052), the more relevant in the female subgroup index. Moreover, positive correlation between DAP and body surface area (p<0.0001) and DT and body surface area (p<0.0001) was demonstrated. Sex, age and body surface area are associated with higher DAP and DT. Apparently our population has lower average diameter aortas that described in the international literature.

KEY WORDS: Aorta; Abdominal Aorta; Abdominal aortic diameter; Aortic Aneurysm; Abdominal; Abdominal/ ultrasonography; ; Cross-Sectional Studies.