Purpose or Case Report: Developmental anomalies of the thumb are frequently encountered in pediatric musculoskeletal imaging and are the most common digital anomalies present in the hands. They often result in functional limitations given the role of the thumb in the normal hand function. Radiological evaluation is essential for diagnosis and treatment planning (whether conservative management or surgical correction). The purpose of this educational poster is to review common congenital thumb anomalies ranging from absence to duplication and to provide a diagnostic approach for diagnosing these anomalies.

The normal prenatal and postnatal development of the thumb is reviewed with attention on skeletal development along with the associated development of the muscles and tendons. Radiographic, ultrasound, and MR imaging is provided to illustrate the range of tissue anomalies that occur throughout thumb development. Specific examples of abnormal thumb development are discussed and illustrated (e.g., preaxial polydactyly, hypoplasia, triphalangeal thumb). Multiple associated developmental anomalies are also reviewed (e.g., Holt-Oram syndrome, thrombocytopenia absent radius syndrome, arthrogryposis multiplex congenita).

A diagnostic approach is provided to help differentiate the various causes of abnormal thumb development using a multimodal imaging approach. When available, longitudinal imaging, physical examination, and surgical correlations are provided for diagnostic confirmation. Possible complications and associated abnormalities are discussed to provide additional considerations for treatment planning. Reporting recommendations are also provided to better facilitate next steps in patient management with the goal of maximizing thumb function. At the end of this module, viewers will be able to better identify and classify thumb anomalies and provide important diagnostic information for guiding patient care.
Methods & Materials:
Results:
Conclusions: