Embryonic development of nasal septum in indigenous sheep

Abstract

The study included detection the onset time of the chondrification and ossification of the nasal septum in indigenous sheep fetuses. Fetuses have been prepared by using stained with modified double staining method in young ages and maceration with potassium hydroxide in older ages. The first sign of nasal septum demonstrated as a small spot of condensed mesenchyme of medial nasal prominence of Meckel's cartilage (Hyaline cartilage). Chondrification process of nasal septum initiated at 54 days old. The primary ossification center of the caudal part of nasal septum appeared at 61 days old in the distal caudal end of mesenchyme of Meckel's cartilage. The examination of nasal septum growth from sheep embryos in the (42-63 days) period shows that this is a rapid period of growth is at the end of the first trimester and the first or second trimester of gestation. The increase in the length of the nasal septum is about three folds (from 0.5 cm at 7 weeks to 1.6 cm at the 10 weeks of indigenous fetal age. The results of analysis of variance done on the relative increase in the nasal septum length and nasal septum height showed that the greatest relative increase in nasal septum length was at the 7 weeks, while the greatest relative increase in the nasal septum height was in the 11 weeks.