By placing the thigh on sono-mount, a fixed ultrasound image is created so that the examiner can use both hands for the puncture. When inserting a pain catheter, the needle can be held in position with one hand and the catheter can be inserted with the other hand under constant sonographic vision. Our design takes into account in particular the aspects of the rotation of the ultrasound probe as well as safety and stability while at the same time being lightweight and inexpensive to manufacture.