Loops

There are two types of loops: radial and ulnar. Radial loops are when the ridges of a fingerprint enter from the side of the finger closest to the thumb; named after the bone in your forearm that connects to your thumb (radius). In a loop fingerprint the ridges turn around and exit the same side that they entered. An ulnar loop, has the same shape but starts and exits on the side closest to the little finger and is also named after the bone in your forearm that connects to your little finger (ulna).
  
radial loop                                     ulnar loop