The extent of inguinal paravascular blockade and psoas compartment blockade with sciatic nerve block was evaluated in 60 patients. Volumes of 30 ml and 20 ml 0.35% bupivacaine with 1/200 000 epinephrine were injected for lumbar plexus and sciatic nerve block, respectively. Complete lumbar plexus blockade was achieved in 73% of the group who were treated with the psoas compartment technique and 43% of the group who were treated with the inguinal paravascular technique. Sensory blockade of the femoral, lateral femoral cutaneous and obturator nerves was obtained in 100%, 97% and 77% of the patients in the psoas compartment group, and 93%, 63% and 47% of the patients in the inguinal paravascular group, respectively. Sensory blockade of the lateral femoral cutaneous and obturator nerves was more rapid with psoas compartment block. The study suggests that the psoas compartment block is effective in blocking the femoral, lateral femoral cutaneous and obturator nerves, but the inguinal paravascular block is only effective in blocking the femoral nerve.