RESUMO
A Study on the pattern of lumbar plexus was performed in 83 plexus; 42 right and 41 left. The lumbar plexus, generally is formed by the ventral rami of the first lumbar spinal nerve to the fourth lumbar spinal nerve in 68.7 percent. There is no difference in origin of lumbar plexus between right and left side and between sexes. In 75.0 percent of the iliohypogastric nerve is formed by the ventral rami of the first lumbar spinal nerve. In 81.9 percent of the ilio-hypogastric nerve is formed by the ventral rami of the first lumbar spinal nerve. In 74.7 percent of the genitofemoral nerve is formed by the ventral rami of the first and second lumbar spinal nerve. In 71.0 percent of the lateral cutaneous nerve of thigh is formed by the ventral rami of the second and third lumbar spinal nerve. In 89.2 percent of the femoral nerve is formed by the second, third and fourth lumbar spinal nerve. In 90.4 percent of the obturator nerve is formed by the second, third and fourth lumbar spinal nerve.