Some ultrasound artifacts may occur as a result of probe defects and malfunctions, necessitating routine quality evaluation of the equipment. Common causes of grayscale ultrasound artifacts include improper focal zone adjustment, ultrasound signal attenuation, variations in sound speed across tissue impedance, and sound refraction, whereas Doppler artifacts encompass motion, twinkling, reverberation, noise, or blooming. Ultrasound artifacts manifest when the probe is not perpendicular to the scanned area, resulting in suboptimal image quality and potentially inaccurate diagnoses. This section delves into both grayscale and important Doppler ultrasound artifacts in rheumatic conditions.