Orientation of human respiratory cilia.

Ciliary orientation was studied on the respiratory epithelium of the nasal cavity or the sphenoidal sinus of ten adult nonsmokers without respiratory disease. The ciliary orientation was evaluated from micrographs by measuring the angle between the plane defined by the central tubules and reference line (with a semiautomatic image analyser (IBAS I]. The standard deviation of the angles of cilia population was counted in every field. The standard deviation of the measurements described the ciliary alignment. It varied from 12.1-41.2 degrees. The mean standard deviation was 27.3 +/- 7.4 degrees. 58% of all measured cilia were within +/- 0-20 degrees of the mean and 85% of cilia were within +/- degrees. However, a few cilia or small groups of cilia were found in most fields which differed dramatically from the main orientation. The size of these groups was always less than ten cilia. On the normal respiratory epithelium the standard deviation of ciliary orientation varies between +/- 10-40 degrees (at about 97% probability). For diagnostic conclusions more than 60 cilia should be measured.