A frenulum is a piece of tissue that prevents an organ from moving. There is a frenulum that attaches your upper lip to the gums, while another connects the lower lip to the gums. A frenulum that is too short or thick, will cause problems in speech patterns and tooth misalignment. In infants, a shortened frenulum underneath the tongue will inhibit breastfeeding. When the frenulum disrupts movement, growth, or development, corrective action is necessary to resolve the situation.