Laryngeal atresia is a rare congenital condition that presents with hypoxia and failed intubation attempts at birth. When diagnosed prenatally, options exist to obtain airway access during delivery. However, postnatal diagnosis requires a high degree of clinical suspicion and the prompt initiation of surgical airway management in order to avoid morbidity and mortality.

Detailed assessment of the larynx is not easy because of its complex structures and the associated technical difficulties. We performed sonography in multiple planes to assess the laryngeal anatomy and movements of a fetus with laryngeal atresia. The distended trachea ended abruptly with an echogenic non-structured larynx which showed shallow rapid \"flutter-like\" movements and up and down but not adduction- abduction movements during swallowing. Shadowing from the chin could be reduced by scanning through fluid in the oral cavity or between the transverse processes of vertebrae in a coronal plane.

Congenital high airway obstruction syndrome (CHAOS) is a near fatal condition of multifactorial inheritence, in which the fetus has a dilated trachea, enlarged echogenic lungs, an inverted or flattened diaphagram, and ascites. A case of CHAOS, diagnosed antenatally on USG at 28 weeks of gestation, is being reported here.