The frenulum is a small bit of tissue that secures the tongue to the muscle at floor of the mouth (lingual frenulum) or the lips to the gums (labial frenulum). (nurturenormally.com)
Often it is less obvious and may actually be hidden under the mucosal floor of the mouth. (pregnancy-info.net)
Two years ago, Margaret O'Neill brought her 5 - year - old daughter to Children's Hospital Colorado because the band of tissue that connected her tongue to the floor of her mouth was too tight. (businessinsider.com)