 If the toebox does not have enough room around the toes, or the foot can slide forwards far enough to jam the toes into the end of the toebox, it can also cause black toenail (jogger's toe).The toes also need vertical space; a toe cap which is low enough to press on the top of the toe may also cause bruising under the nail, especially if the toe cap is stiff.If the toebox is pointed, the toes may be wedged forwards into the area with inadequate height.