Tongue-Tie: history, development and possible causes

Tongue-tie, also known as ankyloglossia, has been recognised for centuries, but its definition, clinical significance and management continue to be debated. Although the condition is often described in terms of a short or tight lingual frenulum, the appearance of the tissue alone does not establish whether tongue movement is functionally restricted (Mills et al., 2019a).

Understanding tongue-tie involves more than examining the tissue beneath the tongue. Its development begins before birth, and variation in anatomy may reflect a combination of genetic and developmental influences. However, the precise causes of tongue-tie remain incompletely understood.

This article explores the historical development of tongue-tie treatment, the embryological development of the tongue and lingual frenulum, and the evidence concerning possible genetic, familial and environmental influences.

What is a 'tongue-tie'?

The lingual frenulum is a normal anatomical structure beneath the tongue. It is not simply a discrete string or band that exists independently of the surrounding tissues. Anatomical research has demonstrated that it is formed by a dynamic fold of oral mucosa and the underlying fascia of the floor of the mouth. Its appearance changes as the tongue moves, and its thickness and composition vary between individuals (Mills et al., 2019a; Mills et al., 2019b; Mills et al., 2020).

Ankyloglossia is a clinical diagnosis in which the lingual frenulum is considered to restrict tongue mobility. The distinction is important: everyone has a lingual frenulum, but not everyone has a tongue-tie that restricts function. Research has also highlighted the limitations of classifying tongue-tie by visual appearance alone, because the relationship between the appearance of the frenulum and functional restriction is not straightforward (Mills et al., 2019a).

The term tongue-tie is therefore best understood in relation to function, rather than as a description of every variation in frenulum appearance.

Historical development of tongue-tie treatment

Biblical period

One frequently cited historical reference appears in the Gospel of Mark. Mark 7:35 describes a man's tongue being loosened, after which he was able to speak plainly. This passage has been discussed in relation to tongue-tie, although the biblical account does not establish that the man had ankyloglossia (Levy, 1995).

5th–4th century BCE

Hippocrates is associated with the early Greek medical tradition in which anatomical conditions were considered in relation to health and function. Historical accounts trace the discussion of tongue restriction and its treatment to ancient medicine.

Accounts of early cutting methods describe variation in the materials and instruments used, including references to blades such as axe blades and in some countries; sharp-edged leaves. These accounts sit alongside the broader history of early practices for releasing tissue beneath the tongue.

1st century CE

The Roman physician Aulus Cornelius Celsus described a tongue attachment that could affect speech in De Medicina. His account included holding the tongue with forceps and incising the membrane beneath it. He warned of bleeding because of the blood vessels in the area and recognised that division would not necessarily resolve every speech difficulty (Celsus, De Medicina, Book VII, Chapter 12).

Medieval period

Historical accounts describe midwives using their fingernails to release the tissue beneath the tongue, while surgeons used cutting instruments. These practices reflected the different roles of midwives and surgeons at the time (Obladen, 2010).

16th–17th centuries

Surgical texts and illustrations documented a range of techniques, including holding the tongue forward while cutting the frenulum with a small knife, and using scissors or instruments to lift the tongue and expose the tissue.

Some accounts describe midwives keeping a fingernail sharp to release the tongues of newborn babies. Such reports demonstrate that the practice existed, although they do not establish that it was universal (Ganesan, Girgis and Mitchell, 2019).

18th century

Surgeons described instruments such as spatulas and grooved directors to lift the tongue and make the frenulum more accessible. These instruments helped practitioners visualise the tissue and control the incision, with the aim of avoiding injury to deeper structures. Bleeding remained a recognised complication (Ganesan, Girgis and Mitchell, 2019).

19th–early 20th centuries

Tongue-tie division was undertaken for a range of perceived difficulties, including speech and feeding problems. In the early twentieth century, the procedure was reportedly performed routinely in some settings.

As bottle-feeding became more common during the twentieth century, fewer infants depended on breastfeeding to receive their milk. This may have influenced how often tongue-tie was recognised as a potential feeding difficulty and whether division was considered. The historical literature describes a decline in tongue-tie division during this period, although changes in infant-feeding practices were only one possible influence (Ganesan, Girgis and Mitchell, 2019; Obladen, 2010).

1981

The World Health Assembly adopted the International Code of Marketing of Breast-milk Substitutes on 21 May 1981. The Code was developed in response to concerns about the promotion of breast-milk substitutes and declining breastfeeding. Its aim is to protect and support breastfeeding while ensuring that breast-milk substitutes are available and appropriately used when needed. Its scope includes breast-milk substitutes, feeding bottles and teats (World Health Organization, 1981).

The Code was not a tongue-tie treatment guideline, but it forms part of the wider history of infant-feeding policy and the protection of breastfeeding.

Late 20th century to present

As breastfeeding support and awareness increased, interest in the possible effects of restricted tongue movement on feeding also returned. Tongue-tie division again became a subject of clinical discussion and research.

Contemporary assessment places greater emphasis on whether the frenulum restricts tongue function and whether this is associated with difficulties for the individual feeding dyad, rather than relying on appearance alone. The presence of a lingual frenulum is normal anatomy; the clinical question is whether its structure and movement are associated with meaningful functional restriction (Mills et al., 2019a; Ganesan, Girgis and Mitchell, 2019).

2019

On 8 February 2019, the Care Quality Commission (CQC) confirmed that frenulotomy carried out by, or under the supervision of, a healthcare professional falls within the regulated activity of surgical procedures. Providers carrying on this regulated activity are legally required to register with CQC. Registration is a statutory obligation, not an optional accreditation (Care Quality Commission, 2019).

This forms part of the modern regulatory framework for tongue-tie division in independent healthcare settings in England.

Embryological development of the tongue and lingual frenulum

The tongue begins developing during the fourth week of gestation, through a complex process involving tissues associated with the pharyngeal arches. The anterior two-thirds and posterior third of the tongue have different embryological origins, and development involves coordinated changes in tissue growth, differentiation and organisation (Nie, 2005).

Historically, tongue-tie was explained by the theory that incomplete apoptosis during embryological development prevented the tissues beneath the tongue from separating fully. Apoptosis is programmed cell death, a normal process involved in embryonic development. Under this proposed mechanism, tissue that would ordinarily regress was thought to persist beneath the tongue, restricting its movement. Although this explanation continues to appear in medical literature, it is a traditional developmental hypothesis rather than an established cause of human ankyloglossia.

More recent anatomical research has challenged the concept of the lingual frenulum as a discrete remnant of tissue that failed to disappear. Instead, the frenulum has been described as a dynamic, three-dimensional fold of oral mucosa and underlying floor-of-mouth fascia, whose appearance changes with tongue movement. As the tongue elevates or retracts, tension and movement within these tissues draw them into a midline fold (Mills et al., 2019a; Mills et al., 2019b; Mills et al., 2020).

This dynamic model offers a different anatomical framework from the older explanation based on incomplete tissue separation. It also raises questions about how tissue development, individual anatomical variation and mechanical forces may interact during development. Fetal movement is part of normal development, but the precise contribution of movement and mechanical forces to the formation of the lingual frenulum, and to the restricted mobility experienced by some individuals, has not been established.

The lingual frenulum is therefore best understood in the context of the wider structures beneath the tongue, rather than as an isolated band whose appearance alone determines function. Research has demonstrated variation in its morphology, while the relationship between individual anatomical features and functional restriction remains incompletely understood (Mills et al., 2019a; Mills et al., 2019b). Although apoptosis is a recognised biological process, evidence that it occurs during tongue development does not establish incomplete apoptosis as the cause of tongue-tie. The precise developmental mechanisms underlying ankyloglossia remain uncertain, and further research is needed to clarify how embryological processes, tissue organisation and mechanical influences may contribute.

Tongue-tie, palate development, sleep and neurodivergence

Tongue posture plays a role in the development of the palate. Where tongue movement is restricted, this may affect how the tongue rests against the roof of the mouth during development. Research has identified an association between a short lingual frenulum, a high-arched palate and obstructive sleep apnoea in children (Camañes-Gonzalvo et al., 2024).

A high-arched palate and other differences in oral and facial structure may be relevant to upper-airway function and sleep. Sleep-disordered breathing can disrupt sleep and affect attention, behaviour and emotional regulation. These effects may overlap with features of attention-deficit/hyperactivity disorder (ADHD), and sleep difficulties are also reported in neurodivergent children.

Won et al. (2017) discussed these possible relationships in a clinical case involving a child with ADHD symptoms and obstructive sleep apnoea. However, although links between tongue-tie, palate shape, sleep and neurodevelopment are being investigated, the evidence does not establish that tongue-tie causes ADHD or neurodivergence. Further research is needed to understand how these factors may be related.

Genetic and familial influences

Tongue-tie can occur in isolation, but familial patterns have also been reported. This has led researchers to investigate whether genetic factors contribute to its development.

A pedigree study involving 149 patients reported familial clustering and suggested a possible X-linked pattern of inheritance in some cases. The study provides evidence that genetic influences may be relevant, but its findings should not be interpreted as demonstrating that all tongue-tie is inherited in the same way (Klockars and Pitkäranta, 2009; A study on the genetic inheritance of ankyloglossia based on pedigree analysis, 2012).

Ankyloglossia has also been described in association with certain uncommon genetic syndromes, including X-linked cleft palate syndrome. However, most people with tongue-tie do not have a recognised congenital syndrome (StatPearls, 2023).

The available evidence is consistent with genetic influences contributing to at least some cases, but the inheritance patterns, genes involved and interactions with other developmental factors are not fully established. A family history may therefore be relevant without being necessary for tongue-tie to occur.

Gender differences

Several studies and clinical reviews report that tongue-tie is diagnosed more frequently in males than females. However, reported prevalence varies considerably between studies, partly because researchers and clinicians use different definitions and diagnostic criteria (StatPearls, 2023; Shivji, Chandrasekara and Ria, 2026).

Differences in reported prevalence do not, on their own, establish the biological explanation for the sex difference. Genetic influences, including possible sex-linked inheritance in some families, have been proposed, but the evidence does not establish one mechanism that explains all cases.

It is also important to consider ascertainment: differences in who is assessed, which diagnostic criteria are used and whether studies include newborns or older children can influence the reported sex ratio. The apparent difference should therefore be interpreted in the context of each study rather than as a universal rule.

Folic acid and the proposed association with tongue-tie

Folic acid supplementation before conception and during early pregnancy is recommended because it reduces the risk of neural tube defects. Concerns have circulated that folic acid supplementation might increase the likelihood of tongue-tie, partly following a hypothesis proposed in a 2020 study.

That case-control study reported an association between regular preconception folic acid use and tongue-tie in the infants studied. However, an association in a single observational study does not establish causation, and the study had methodological limitations (Amitai et al., 2020).

A systematic review published in 2023 examined the available evidence and found only one directly relevant study. The reviewers concluded that the evidence was insufficient to establish a relationship between maternal folic acid supplementation and ankyloglossia. They also found no research evidence establishing a mechanism by which supplementation would cause tongue-tie (Rubin et al., 2023).

The proposed association must therefore be treated as an unconfirmed hypothesis, not an established cause. The known benefits of folic acid supplementation in preventing neural tube defects substantially outweigh the unproven concern about tongue-tie. People planning a pregnancy or who may become pregnant should continue to follow current UK recommendations on folic acid.

A multifactorial explanation remains possible

The available evidence does not establish one cause that explains every case of tongue-tie. Developmental processes, variation in tissue formation and genetic influences may all be relevant, but the relative contribution of each remains uncertain.

It is also important to separate the development of a frenulum from the question of whether it restricts function. A visible frenulum, a particular attachment point or a family history cannot independently determine the functional significance of the tissue. Anatomical assessment needs to be considered alongside tongue mobility and the individual’s functional presentation (Mills et al., 2019a; Mills et al., 2020).

Research continues to examine the relationship between frenulum anatomy, tongue movement and clinical outcomes. Better understanding of these relationships may help clarify why some individuals experience functional restriction while others with a similar-looking frenulum do not.

Conclusion

Tongue-tie has a long history, from early descriptions of tongue restriction and surgical division to contemporary discussion of feeding function, anatomy and clinical oversight. Although proposed explanations include altered embryological development and genetic influences, the precise causes of ankyloglossia remain incompletely understood.

Current anatomical research demonstrates that the lingual frenulum is a dynamic structure with considerable variation between individuals. Its appearance alone does not establish whether it restricts tongue movement. A careful distinction between anatomical variation, functional restriction and proposed causes is therefore essential when interpreting the evidence.

Further research into embryological development, genetic influences and the relationship between anatomy and function will be important in improving understanding of this condition.

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