How to perform ultrasound-guided injections.

Among the most important reasons for the increased use of ultrasound by rheumatologists is its feasibility to guide injections. Correct positioning of the needle in the targeted structure occurs much more frequently with ultrasound guidance than with conventional positioning without imaging. The sonographer can mark the skin above the structure, using ultrasound to localize this point and to estimate the depth of the structure. Alternatively, the sonographer might introduce the needle under direct sonographic visualisation, holding the probe in one hand and the needle in the other. The needle can be longitudinally parallel to the probe, with an angle of about 45 degrees to the probe. It can be introduced close to the middle of the probe or opposite the probe; the needle can be also depicted transversely. Ultrasound allows needle guidance in nearly all important structures of shoulders, elbows, hand, hips, knees and feet. Education involves training to coordinate probe and needle in sponges, chicken, cheese and other objects. Knowledge of anatomy, probe positioning and the ability to coordinate probe and needle are necessary when injecting patients with sonographic guidance. The rheumatologist might start with easy approaches in which the needle is parallel to the probe.