Ultrasound-guided interventional procedures in the musculoskeletal system.

Ultrasound is a low-cost, nonionizing, readily available diagnostic technique for the evaluation of tendons, muscles, soft tissue masses, cysts, and other fluid collections. Ultrasound is also a valuable tool for guiding a variety of musculoskeletal interventions. Procedures that can be performed under ultrasound guidance include aspiration of fluid for analysis, injection for medication, decompression of cysts, drainage of abscess and hematoma, biopsy, treatment of calcified tendinitis, and foreign body retrieval.