Lumbar Radiculopathy Explained Ever feel pain shooting down your leg? It might not be your leg -it could be your spine. L3 - Pain in the front of the thigh L4 - Inner shin and ankle discomfort L5 - Outer thigh, shin, and top of foot S1 - Pain down the back of the leg to the pinky toe These patterns are called dermatomes, and they trace the path of irritated nerve roots from your lumbar spine. A disc bulge, herniation, or spinal narrowing can press on these nerves and radiate pain far from the actual problem area.