Diagnostic and therapeutic interventional procedures are rapidly expanding and, when guided by imaging, are more efficient then when performed with a blinded technique. Compared to fluoroscopy and CT, ultrasound does not utilize ionizing radiation. It can facilitate needle placement for arthrography, tenography or bursography or it can guide a variety of procedures such as aspiration, arthrocentesis, local steroid injections and needling of tendon calcifications. Technological improvements have increased the precision of ultrasound guidance and have contributed to reduce the risk of complication. Real time scanning allows simultaneous visualization of the target and of needle progression and has diminished the rate of complications, that are infrequent if the operator uses a strict sterile technique and respects the contraindications.