The heads, palates and nasal cavities of mice embryos with cleft palate caused by various abnormal intrauterine environments, which were induced with Trypan blue, Cortisone, Carzinophilin and noise stimulation, were morphologically studied.
Results obtained were as follows :
1) Most of those clefts were median and complete without lip- or alveolarcleft. Partial unilateral cleft was produced in each one case with 5% Trypan blue, Carzino-philin and Cortisone.
2) As to the type of cleft, the width at the ventral and the dorsal edge were almost equal in most cases, and the dorsal edge was very wider in other few cases.
3) The width of the palate showed no difference between the abnormal embryos and the controlled normal embryos. The arch of palate was high in the 2 embryos with cleft palates. The width of the left and the right palatal process were not in most cases equal.
4) Squamous epithelium was observed on the nasal side of palatal process.
5) Glycogen granules contained in palatal epithelium and the epithelium of nasopalatine canal were less in embryos with cleft palate than in the controlled embryos.
6) The heads of some cases were flat or asymmetrical.
7) Deviation of the nasal septum was seen in 3 cases.
8) Asymmetry of the shape and width of the nasal cavity, inhibitory development of the concha and the paranasal sinus and depressed development and asymmetry of the nasal gland were apparently observed in the Trypan blue group, but not so clearly in other groups.
9) In all abnormal embryos, the transverse diameter of the nasopharyngeal duct was wider; in most cases, the cranial wall of the duct was thinner.
10) Depressed development and asymmetrical development of the maxillary bone, vomer and palatal bone could also be observed.
11) In most cases, the development of the teeth anlage was normal, but was inhibited in some of the Cortisone group.