Musculoskeletal ultrasound of the upper extremity in children.

Musculoskeletal US is becoming more widely performed in children. Although overlap between pediatric and adult pathology exists, particularly in older children who have a more mature skeleton, there are significant differences when assessing patients who have cartilaginous ossification centers, particularly in the context of trauma. Lack of ionizing radiation and dynamic imaging capabilities are significant advantages compared to CT and MRI. Although MRI provides excellent evaluation of soft tissues, the need for general anesthesia in a subset of patients is undesirable, particularly when US can provide similar information. Radiography is the primary modality to evaluate trauma; however, musculoskeletal US can be useful to assess alignment of unossified structures, fractures that extend to involve the unossified epiphyses, occult fractures, physeal separation, presence of intra-articular bodies (particularly those that are not ossified), ligamentous injury and the occasionally encountered periosteum trapped between fracture fragments. The purpose of this article is to review commonly encountered pathologies unique to the pediatric upper extremities that are ideally imaged with sonography. Some pathology that overlaps with the adult population such as infection and sports injuries are briefly covered.