The nature of ultrasound waves being reflected, refracted and scattered is the corner stone for the principle of action of ultrasound which makes it possible to visualize different tissues with various depth from the probe. Different techniques were proposed for peripheral nerve blocks which describe mainly the blocks for upper limb, lower limb and abdominal wall blocks which provide intra and post operative anaesthesia and analgesia in pediatrics which are becoming more easy and effective using the ultrasound units.