US-guided injection of the upper and lower extremity joints.

There is a growing interest in the application of ultrasound (US) guidance for diagnostic and therapeutic joint injections. US provides direct visualization of soft tissues and the outer borders of bony structures. With real-time needle guidance the success rate of intra-articular injections improves and iatrogenic damage to anatomic structures can be avoided. An US machine is more readily available, transferrable and more affordable than a fluoroscopy machine or CT scanner and lacks the risk of radiation. These factors make US a valuable alternative to procedures performed either blind or under fluoroscopic or CT guidance. This article focuses on the rationale for injections in the upper and lower extremity joints and describes and illustrates the different US-guided injection techniques.