Sensory and motor innervation of the whole lower limb is due to lumbo-sacral-plexus that arises from the spinal roots L1-S3. The whole lower limb can be blocked from its origin to the foot for surgical procedures or for postoperative analgesia. Single or continuous lumbar plexus blockade can be an alternative to general anesthesia and central block in elective and traumatic hip or femur repair, for knee surgery and for postoperative analgesia. To understand the relative plexus depth and the relationship between the plexus and the closer structure in order to avoid complicance, the aid of imaging technique such as CT-scan, MRI and ultrasounds can be considered.