Reviewed by: BD Editors

Frenulum Definition

A frenulum is a small ridge or fold of skin that helps to anchor a semi-mobile body part. In the human body, frenulums are found on the penis, under the tongue, inside the lips, as part of the female genitalia, and internally in the brain and digestive tract.

An oral frenulum, the , is pictured below. This person has gotten their frenulum labii superioris pierced.
Lip frenulum piercing closeup

Because the two most important locations of frenulums outside the body are in the mouth and on the genitalia, “frenulums” are most often discussed either in dentistry and oral health, or in reproductive health and sexual advice.

While these structures often go unnoticed in the healthy body, frenulums which are too thick or too short can lead to health problems. Unusually short or thick frenulums can also be symptoms indicating more serious illnesses, such as genetic syndromes that may effect both the development of the frenulum and the internal organs.

Internal frenulums such as those found in the gut and brain are rarely discussed or operated on except when they are subject to internal injury. As a result, most people do not even know they exist!

Function of Frenulum

The term “frenulum” comes from the Latin term meaning “little bridle.” As the name suggests, frenulums help to “rein in” organs and structures that are not completely connected to each other.

In the mouth, the function of frenulums is obvious: the lips, cheeks, and tongue are largely separate from the jaw. The presence of intermittent thick skin folds connecting these structures helps them to remain anchored and properly aligned with the jaw.

A similar purpose is served by genital frenulums, which similarly help to connect external sheaths of skin and tissue to the reproductive organs they are supposed to be protecting.

Frenulums may sometimes be surgically cut in cases where they are unusually strong and thick, resulting in unusual restraint of the mouth or genitalia. They may also be cut as part of circumcision.

In rare cases, “frenulum” may refer to a part of the anatomy of moths. We will not discuss the moth anatomical characteristic here.

Examples of Frenulum

Oral Frenulums

In the mouth, one frenulum can be found under your tongue. The thick band of skin that runs along the under side of your tongue, anchoring it to the bottom of your mouth, is the “frenulum linguae.” The smaller bands of skin many people have running between their lips and front teeth are “frenulum labii.

Some people also have bands of tissue connecting the jaw to the cheek at various points, which are called “buccal frena.” In some cases, dentists might elect to cut one or both of the frenulum labii, since especially thick frenulums can pull teeth together and effect their alignment.

Dentists may sometimes cut oral frenulums, if they are unusually thick and cause problems for the mobility or alignment of the jaw or teeth. This can often be done painlessly with local anesthetic.

Doctors also sometimes use oral frenulums to look for signs of violence or abuse in a patient. Because oral frenulums are easily torn by impacts or jerking movements, torn or scarred oral frenulums can be a clue that a patient has experienced violence.

Genital Frenulums

In the penis, the frenulum of prepuce of penis anchors the foreskin to the glans. In uncircumcised people, this helps the foreskin to contract over the penis, protecting it. Circumcision may involve removal of the frenulum of the penis as well as the foreskin.

The frenulum is considered be one of the most sensitive parts of the penis to touch. Stimulation of the frenulum alone has been found to produce orgasm in some men, and some men retain feeling in their frenulum and surrounding issues even after spinal cord injury.

The frenulum of the penis can also cause significant bleeding if injured due to the presence of a small artery in the frenulum.

Frenulums which, like those of the penis, contain small blood vessels, can also be found helping to anchor structures near the clitoris and the bottom opening of the vagina.

Circumcision of men, which involves removal of the foreskin and sometimes the frenulum, is presently a controversial practice in the medical community. Some doctors believe that circumcision prevents certain diseases and disorders of the penis, while others feel that it removes the penis’ natural protection and is mostly performed for religious and cosmetic reasons that may ultimately be harmful to the health of men and boys.

“Female circumcision,” which often involves cutting of other genital parts such as the clitoris and labia, is not the same procedure as male circumcision and is often referred to by doctors as “female genital mutilation,” because it is anatomically more comparable to cutting off most or all of the penis than to the removal of the male foreskin and frenulum.

There are no medical benefits to female circumcision, which typically results in severe damage to female sexual functioning and may sometimes result in dangerous bleeding or infections. Many governments in Africa and the Middle East have mounted campaigns to discourage female genital mutilation, which is traditional among some groups in those regions.

Internal Frenulums

Frenulums inside the body that don’t normally see the light of day include the frenulum veli in the brain and the frenulum valvae ilocaecalis in the digestive tract.


1. In which of the following settings would you expect to hear frenulums being discussed?
A. In a dentist’s office
B. In a sexual health clinic
C. In an operating room
D. All of the above

Answer to Question #1
D is correct. All of the above are places where frenulums might be discussed!

2. Which of the following body parts does NOT have a frenulum?
A. The mouth
B. The brain
C. The genitals
D. None of the above

Answer to Question #2
D is correct. All of the above organs have at least one frenulum!

3. Why are structures in such different organs as the mouth, genitals, and brain all referred to as “frenulums?”
A. Because “frenulum” is the name for an anatomical structure that helps to anchor two body parts together.
B. Because scientists named these body parts independently, without consulting each other.
C. Because the structures all look a bit similar.
D. A and C.

Answer to Question #3
D is correct. “Frenulum” refers to any band of skin that helps to anchor a body structure. Because frenulums serve a similar biological function, they also tend to look similar to each other.


  • Priyanka, M., Emmadi, P., Ambalavanan, N., Sruthi, R., & Ramakrishnan, T. (2013). An overview of frenal attachments. Journal of Indian Society of Periodontology, 17(1), 12. doi:10.4103/0972 124x.107467
  • Frenulum. (n.d.). Retrieved from

Cite This Article

MLAAPAChicago Editors. "Frenulum." Biology Dictionary,, 23 Jun. 2017, Editors. (2017, June 23). Frenulum. Retrieved from Editors. "Frenulum." Biology Dictionary., June 23, 2017.

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