Low, medium and high wrist are a few of the terms used to describe grip styles. Medium and high wrist are what is on most recurves. With these, the pressure point on the throat of the grip is greatest in the web of the bow hand between the thumb and index finger and the palm rests fairly gently, if at all, on the lower part of the grip. A low wrist calls for a bending the wrist such that more of the palm of the hand or heel puts pressure on the entire grip area.
Any of these styles can position your hand right under the shelf. Generally that's considered a good thing because it helps align the arrow better under your shooting eye. A high wrist grip might "feel" like it's positioning your hand/fingers closer to the shelf, and a low wrist might "feel" like your hand is farther from the shelf, in comparison. In reality, they very well could be the same distance away.