This orthopedic depth measuring ruler is designed for UBE dual-channel minimally invasive spinal surgery. Its slim long shaft slides easily through narrow intervertebral tunnels to accurately measure the depth and size of intervertebral foramens, lateral recesses and bone grooves. The grip is engraved with bumpy anti-slip textures to ensure stable holding during measurement for precise positioning. Uniform clear standard markings run along the shaft, allowing surgeons to instantly check drilling and grooving depth without extra auxiliary tools, preventing over-penetration that harms spinal nerves.