Soft Palate a. A fibromuscular shelf made up of several muscles attached like sling to the posterior portion of the hard palate. Contacts passavant's ridge. Embryology and Genetics A. Genetics and Epidemiology 1. Multifactorial inheritance plays the major role.
Familial inheritance occurs, but classic mendelian inheritance is rare.
Counseling for risk rates for future offspring. Chromosomal aberrations such as trisomy D and E have increased incidence of clefts. In humans only rubella virus, thalidomide and aminopterin have been proven to cause clefts. Overall males are more affected than females. The reason for this difference is because embryologically the mechanism for cleft palate is different than for cleft lip.