Small Thorax
Fig 1, Fig 2
Pulmonary hypoplasia secondary to prolonged oligohydramnios remote from term is the most common cause, however, small thorax can be associated with several causes as follows:
- Pulmonary hypoplasia
- Skeletal dysplasia (such as thanatophoric dysplasia, osteogenesis imperfecta type II, short-rib polydactyly syndrome, Jeune’s syndrome, etc.)
- Severe oligohydramnios secondary to preterm premature rupture of membranes or bilateral renal agenesis
- Neurologic disorder (decreased breathing movements)
- Bilateral lung agenesis (very rare)
Fig 1: Lung hypoplasia Sagittal scan of the trunk: small thorax compared with abdomen (*) in association with chondroectodermal dysplasia
Fig 2: Lung hypoplasia Cross-sectional scan of the thorax and abdomen: small thorax with atrial septal defect (short arrow) and severely short rib (long arrow) in association with Jeune syndrome, compared to abdomen (right)
Video clips of small thorax
Lung hypoplasia / SRP Syndrome: Small thorax (*) with short ribs compared to the head size in case of fetal short-rib polydactyly syndrome