Nonetheless, evolution moves at its own pace – slowly – and approximately 90% of humans still have this vestige trait passed down from our primate progenitor. To determine whether you have this tendon, place your forearm on a table with your palm facing upward. Place your pinky finger next to your thumb and elevate your hand slightly off the surface. If you notice a raised band in the middle of your wrist, you have a tendon attached to the still-existing palmaris longus.