Constriction rings syndrome is a congenital limb malformation disorder with an extremely variable clinical presentation characterized by the presence of partial to complete, congenital, fibrous, circumferential, constriction bands/rings on any part of the body, although a particular predilection for the upper or lower extremities is seen. Phenotypes range from only a mild skin indentation to complete amputation of parts of the fetus (e.g. digits, distal limb). Compression from the rings may lead to edema, skeletal anomalies (e.g. fractures, foot deformities) and, infrequently, neural compromise.

The presence during the prenatal period of a cystic mass with multiple septa with multiple, asymmetric, thin-walled cysts near the posterior aspect of the neck. Fetal cystic hygroma can be defined as nuchal translucency with or without septations measuring greater than 3.0 mm.