cleft palate, incomplete fusion of bones of the palate. The cleft may be confined to the soft palate at the back of the mouth; it may include the hard palate, or roof of the mouth; or it may extend through the gum and lip, producing a gap in the teeth and a cleft lip, which is cosmetically difficult to repair but is not disabling. The condition appears to be hereditary but not under the control of a single pair of genes. A cleft palate causes separation between the oral and nasal cavities. An infant cannot develop proper suction for drinking, and there is the danger of milk entering the nasal cavity and being aspirated into the lungs. Formula must be carefully placed at the back of the tongue for normal swallowing to take place. Ear infection may result from food or fluid passing from the nasal cavity to the middle ear by way of the Eustachian tubes. Proper speech articulation is difficult unless the cleft is surgically closed, with a prosthesis. The proper time for such an operation is in dispute; some authorities prefer early closure, before the cleft interferes with development of normal speech habits, while others prefer to wait for several years until facial growth has been completed. Dental, orthodontic, psychiatric, and speech therapy may be required.