Craniofacial and neck anomalies

Craniofacial disorders are central to the diagnosis of genetic syndromes an d malformations. Not infrequently, a geneticist may diagnose a syndrome jus t by observing the newborn's facial features. The precise role, however, of the craniofacial survey within the standard prenatal sonographic examinati on remains unclear. Although the validity of the craniofacial examination i n a high-risk population was first reported in 1986 by Pilu et al,(22) a de tection rate of only 50% for isolated craniofacial anomalies was reported 1 1 years later by Hafner et al,(9) who studied 5407 low-risk pregnancies. Ne vertheless, rapid developments in modern sonographic technology and molecul ar testing have brought us to point where we can now make definitive prenat al diagnoses of syndromes associated with craniofacial anomalies. It is imp erative to remember that for some lethal disorders, craniofacial anomalies may be the primary presenting feature. Consequently, prenatal detection of such anomalies has great impact on the parental decision-making process. Li kewise, nonlethal abnormalities of this region may result in airway obstruc tion and require lifesaving interventions at birth. The embryologic origin of the head and neck is extremely complex, encoded b y several locally and systemically expressed genes. The interruption of cru cial migration processes results in myriad isolated anomalies, syndromes, s equences, and associations of various causes, thereby necessitating an orga nized approach. This article addresses the sonographic assessment of the he ad and neck by developmental fields, specifically the cranium, midface, lip and palate, mandible, and neck regions. The recognition of craniofacial an d neck anomalies is a key aspect in elevating the second-trimester evaluati on from a routine scan to a superior anatomic survey. It is especially impo rtant to look for minor anomalies, because these may indicate the presence of a more generalized disorder (Table 1).