Ulnar border of digits of hand

The ulnar border of the digits of the hand refers to the anatomical margin of a finger that is oriented toward the ulna, the medial bone of the forearm in the anatomical position. Specifically, for each digit, the ulnar border is the side closest to the little finger (fifth digit) and the ulna itself. For example, in the index finger, the ulnar border is the side facing the middle finger; in the middle finger, it is the side facing the ring finger; in the ring finger, it is the side facing the little finger; and in the little finger, it is the side facing away from the thumb, toward the edge of the hand.