Measurements Of The Bony External Auditory Meatus (Beam) Using Plain Radiographs: Experience From Sokoto, Northwestern Nigeria

Background: The simplest of the parameters in anthropometry, including, height, weight, length, thickness and widths of various parts of the body vary from tribe to tribe and from one race to the other. On the other hand, these measurements also differ amongst different age groups and between the two sexes as well. Design: A retrospective study of the measurements of Bony External Auditory Meatus (BEAM) was undertaken using normal lateral skull radiographs of Nigerians examined in the department of Radiology, Usmanu Danfodiyo University Teaching Hospital (UDUTH), Sokoto, from 2002 to 2004. Methodology: All available lateral skull radiographs of subjects over a 3-year period from 2002 to 2004 were retrieved from the Radiology Department of the Usmanu Danfodiyo University Teaching Hospital, Sokoto for the study. Radiographs were mounted on the viewing boxes and BEAM diameters were measured. Results: A total of 202 subjects were involved in this study. Of this figure, 148 (73%) were males, and 54 (27%) were females (m: f ratio =2.7:1). The age range of all the subjects was 1-60 years (mean 24.6, SD 15.6 years). The vertical diameter ranged from 3mm to 14mm, and the horizontal diameter ranged from 2 to 11mm. The mean BEAM diameters obtained from all the radiographs of the subjects studied were 10.2mm (+-1.7) for vertical and 7.0mm (+-1.6) for horizontal diameters. The BEAM diameters for males were greater than those of their female counterparts, and the differences were statistically significant (p< 0.05 for both vertical and horizontal diameters). The BEAM diameters increase with age (R2 =0.805 and 0.571 for vertical and horizontal diameters respectively). There were statistically significant age related differences (in all the six decades of life) in both vertical and horizontal diameters (