US of the elbow: indications, technique, normal anatomy, and pathologic conditions.

The elbow, a synovial hinge joint, is a common site of disease. Ultrasonography (US) has become an important imaging modality for evaluating pathologic conditions of the elbow. This powerful imaging tool has the advantages of outstanding spatial resolution, clinical correlation with direct patient interaction, dynamic assessment of disease, and the ability to guide interventions. Unlike most other imaging modalities, US allows the contralateral elbow to be imaged simultaneously, providing an internal control and comparison with normal anatomy. A useful approach to US evaluation of the elbow is to divide it into four compartments: anterior, lateral, medial, and posterior. US of the elbow has varied clinical applications, including evaluation and treatment of lateral and medial epicondylitis, imaging of biceps and triceps musculotendinous injuries, evaluation of ulnar collateral ligament laxity, diagnosis of joint effusions and intraarticular bodies, and evaluation of peripheral nerves for neuropathy and subluxation. US can also be used to evaluate soft-tissue masses about the elbow. Knowledge of the normal US anatomy of the elbow, familiarity with the technique of elbow US, and awareness of the US appearances of common pathologic conditions of the elbow along with their potential treatment options will optimize radiologists' diagnostic assessment and improve patient care. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.334125059/-/DC1.