The ‘lingual frenum’ (or lingual frenulum) is the cord that stretches from under the tongue to the floor of the mouth.

‘Tongue tie’, ‘Ankyloglossia’ or ‘short frenum’ are the terms used when the lingual frenum is short and restricts the mobility of the tongue.


Tongue tie can be defined as a structural abnormality of the lingual frenum. When the frenum is normal, it is elastic and does not interfere with the movements of the tongue in sucking, eating, clearing food off the teeth in preparation for swallowing and, of course, in speech. When it is short, thick, tight or broad it has an adverse effect on oromuscular function, feeding and speech. It can also cause problems when it extends from the margin of the tongue and across the floor of the mouth to finish at the base of the teeth.


The frenum is tissue left over from the time the foetus was developing in the mother’s womb and which would normally reduce to insignificance before birth. In the first 3 months of life, the face becomes differentiated into its various parts, and the frenum is what is left of the tissues that should have disappeared as the oral areas are formed. Such vestigial structures are not uncommon, and ‘webbing’, as it is sometimes called, can occur between upper or lower lips and gums, cheeks and gums as well as in tongue tie.


No recent epidemiological studies have been done to estimate the number of people who have tongue tie. A study in 1941 quoted the incidence of tongue tie to be 4 per 1000 of the population. Research at the University of Cincinnati, USA, published in 2002, found that around 16 percent of babies experiencing difficulty with breastfeeding had a tongue tie. Another study at Southampton General Hospital, UK, found that 10 percent of babies born in the area had a tongue tie.

Agreement about the criteria for diagnosis is needed before incidence can be accurately estimated. Actual figures may well be surprisingly higher than expected.
As information about tongue tie and its effects becomes more widely available, more people are diagnosed and treated successfully.


All tongue ties do not look alike – adding to the difficulty of spotting them. They can be thin and membranous, thick and white, short, long or wide, extending from the margin of the tongue all the way to the lower front teeth, or so short and tight that they make a web connecting the tongue to the floor of the mouth.

When they extend to the margin of the tongue, they cause a heart-shaped look at the front of the tongue and no tongue tip can be seen. When they extend across the floor of the mouth they cause pain when the tongue is elevated. They can cause separation or inward tilting of the incisors.

A baby with a tongue tie will look different from an older child with the same condition.

Genetic factors

Tongue tie often runs in families. Some relatives may only have mild effects or no apparent symptoms while others show a severe impact on structure and function. As this strong familial tendency exists, parents may also notice a similarity to other relatives with tongue tie, especially in the older child. The similarities observed may include postures of lips and tongue, habits of speech, and shapes of the nose and face.

Tongue tie sometimes occurs together with other congenital conditions which affect the structure of the mouth, such as cleft lip or palate. It can also occur together with conditions such as severe hearing loss or cerebral palsy. There are more tongue-tied boys than girls.


In making a diagnosis of tongue tie, the two traditional criteria have been acute malnourishment or misarticulation of tongue tip sounds such as ‘t’, ‘d’, and ‘n’.

However, there are several other factors which can be attributed to the limitations of lingual ability that accompany a tongue tie and these should be considered in any assessment of whether a tongue tie exists and whether surgical intervention is warranted. The other factors include:

  • Appearance of the tongue and its movements.
  • Maternal factors including pain, nipple injury, blocked ducts or mastitis during breastfeeding.
  • Infant factors including low weight, vomiting and gagging.
  • Lack of lingual mobility which affects speed and accuracy of tongue movements.
  • Eating difficulties caused by poor coordination of oral musculature.
  • Dribbling – which is prolonged.
  • Dental problems which are severe and wide ranging.
  • Speech which is unclear due to several aspects, especially coordination.


There are several methods of classifying a tongue tie and currently different professions use their own means of assessment. They include the following considerations:

  • Measurements of ‘free tongue’, and height to which the tongue can be lifted.
  • Appearance of the margin of the tongue, and whether indentation is present.
  • Function and ability to protrude or to elevate the tongue
  • Breastfeeding, and any problems experienced.
  • Speech problems.

Assessment of tongue tie in an infant will obviously be different from the same process carried out with an older person.

Lactation consultants may use the Hazelbaker Assessment tool for Lingual Frenulum Function, or rely on their judgement of appearance and any sucking problems experienced.

The Kotlow assessment devised by an American specialist paediatric dentist classifies tongue ties in 4 classes according to the length of free tongue (the distance from the tip of the tongue to the attachment of the frenum). Class I (12-16 mm) is mild, Class II (8-11 mm) is moderate, Class III (3-7 mm) is severe, and Class 4 (<3 mm) is complete. A distance of >16 mm is considered clinically acceptable.

Studies done with breastfeeding infants in Southampton, UK, by Mr Mervyn Griffiths and his team of lactation consultants used a classification based on 3 appearance factors: diaphanous (transparent), medium (non-transparent) or thick (chunky). The percentage of tongue tie was also gauged by eye, ranging from 25% (i.e. extending 25% of the distance along the underside of the tongue) to 100% (i.e. extending all the way to the tip).

Quantitative evaluation of the lingual frenulum was used in research done in Sao Paulo, Brazil, by Dr. Irene Queiroz Marchesan, using a digital calliper to measure the frenums and tongues of adult subjects with tongue tie.

Other disciplines use a classification that divides tongue tie into 4 types depending on the point of attachment of the frenum to the tongue.
The Tongue tie Assessment Protocol (TAP) described in the book “Tongue tie – from Confusion to Clarity” uses both appearance and function to assess its significance. It provides a method by which those aspects affected by tongue tie can be assessed and scored, so that if the final score is below a specified number the need for surgical intervention can be established.


Up to the year 1940, tongue ties were routinely cut to help feeding. When this changed – because of a fear of excessive/unnecessary surgery and a reduction in the practice of breastfeeding – the belief that tongue tie was not a “real” medical problem but an idea held by over-zealous parents became widespread.

Early intervention is ideal since it avoids habit formation and the negative effects of failure: whether it is due to messy or slow eating, funny looking teeth or speech problems. When there are no strong habits to eradicate there is a better chance of success in correcting the difficulties that poor tongue mobility has caused.

Once a tongue tie has been diagnosed, the primary need is to correct the structural anomaly causing the problem. After the structural problem has been successfully corrected, it is reasonable to expect to improve function, and to treat secondary problems successfully. The type of treatment that is most appropriate depends on the problems that have been experienced

A lactation consultant can help with correcting poor sucking which will improve breastfeeding. A speech-language pathologist will help with speech and language problems. A dentist or orthodontist can help with problems of crooked or decayed teeth and infected gums.