incomplete fusion of the palatal shelves, which may be complete or incomplete, unilateral or bilateral. incomplete forms generally affect the secondary palate, posterior to the incisive foramen, and often occur without clefting of the lip. complete palatal clefts usually affect the primary and secondary palate and involve the lip. clefting of the primary palate alone does occur and generally includes a cleft lip. submucous clefts are those defects of the hard and soft palate where a mucosal web bridges the segments. the most frequent form of cleft palate is the bifid uvula, which is found in 2% of the population. a complete unilateral cleft palate is the next most common. midline clefts of the soft palate, which may or may not include part of the posterior hard palate, occur quite frequently. it has been suggested that v-shaped clefts of the palate are malformations whilst u-shaped clefts are deformations resulting from interference with palate shelf closure by the tongue. these latter clefts are often associated with micrognathia in the robin sequence. the incidence of isolated cleft palate is 4 to 5 per 10,000, and shows no racial or ethnic variation, in contrast to cleft lip and palate. complete clefts of the secondary palate are twice as common in females, whilst clefts of the velum show the opposite sex predominance. it is reported that up to 50% of infants with an isolated cleft palate have other congenital anomalies. many syndromic associations are noted.
sonographic diagnosis of isolated cleft palate is difficult and axial and coronal views should be obtained. published reports have focussed on postnatal confirmation of disruption of palatal integrity in suspicious cases where lip clefting was also a feature. one explanation may be the technical difficulty of imaging the palate, especially in comparison to imaging the lips. this is particularly true in the third trimester with descent of the head into the pelvis. ancillary signs of cleft palate include polyhydramnios and a small or non-visible fetal stomach. these findings are attributed to abnormal swallowing mechanisms and passage of amniotic fluid through the cleft palate into the nasopharynx and back into the amniotic sac. colour doppler imaging techniques have documented these altered oronasopharyngeal fluid dynamics in palatal clefting.
an atypical oro-ocular cleft may involve the palate but will be associated with bizarre clefting of facial structures, anomalous spacing of the eyes, abnormalities of eye size and deformation of the nose. cleft lip and palate is more common than isolated cleft palate. a thorough evaluation of the continuity of the lip should be made whenever a cleft palate is seen. median cleft face with cranium bifidum and wide-spacing of facial structures can be associated with cleft palate.
bony defect of the palate on coronal image
polyhydramnios small or non-visible stomach
turbulent movement of fluid through the bony palate during swallowing, demonstrated by colour doppler
- chromosome: trisomies 9, 13; duplications 3p, 7p,7q,8q,9q,10p,11p,14q,17q,19q; deletions 4q,7p,
- cleft palate – isolated
- cleft palate – x-linked
- femoral hypoplasia-unusual
- hypertelorism-hypospadias (opitz g)
- multiple pterygium
- oto-palato-digital, type i
- oto-palato-digital, type ii
- skeletal dysplasias
- treacher collins
- lettieri j in: human malformations and related anomalies oxford university press, pp375-80
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