A frenulum (plural frenula or frena) is a short fold or band of tissue that anchors or limits the motion of a mobile organ or structure. In human anatomy frenula are folds of mucous membrane, connective tissue and small blood vessels and nerves that help stabilize parts such as the tongue, lips and genitalia while permitting necessary movement.
Common locations and function
Well-known human examples include the lingual frenulum under the tongue, the upper and lower labial frenula between lips and gums, and the penile frenulum on the underside of the glans. These structures help position organs, protect delicate junctions, and can influence function such as speech, feeding and sexual sensation.
Clinical relevance
Variations or abnormalities of frenula can have practical consequences. A tight lingual frenulum (ankyloglossia or "tongue‑tie") may interfere with breastfeeding and articulation; labial frenula can contribute to a gap between front teeth (diastema); a short penile frenulum may cause pain with erection. Treatments range from conservative management to minor procedures such as frenotomy or frenectomy to release the fold.
Development and distinction
Frenula form during embryologic development as tissues differentiate and are usually small and flexible. They differ from ligaments—which connect bone to bone—by being thinner, mucosal, and largely concerned with limiting soft‑tissue motion rather than stabilizing skeletal parts.
In zoology and other animals
The term also appears in zoology. For example, some moths and other insects possess a frenulum that couples the forewing and hindwing to improve flight stability; see wing coupling. General information about biological topics is available under zoology and references to specific organs appear under broader entries for the organ or the body.