What is a superior labial frenulum? An anatomical and histological study

Abstract

Anatomy of the superior labial frenulum (SLF), at first glance, seems to be well established. However, existing studies on the SLF lack description of the incisivus labii superioris (ILS), which cannot be ignored when discussing the SLF. We believe that thorough understanding of the SLF necessitates the anatomical knowledge of the ILS. This study aimed to elucidate the anatomical relationship between the orbicularis oris (OO), ILS, and SLF. A total of 20 formalin fixed human cadaveric specimens were used for gross anatomical and/or histological observation. For histological observation, all specimens were stained with Masson‐trichrome. The SLF was a mucosal fold between the gingival mucosa and alveolar mucosa with connective tissue deep to it. The connective tissue attached to the alveolar bone in the junction between the right and left ILS. Skeletal muscle fibers other than orbicularis oris was found in one specimen, which were considered the ILS. During a frenulectomy, removal of the connective tissue bundle is required to prevent recurrence of the high SLF insertion.

Prevalence of Maxillary and Mandibular Frenal Attachment and Its Association with Age, Gender, and Oral Hygiene Status in Nepalese Population Seeking Dental Treatment

“…The frenum is a component of the mucous membrane, taking the form of a fibrous collagenous band, that serves to connect the lips to the alveolar mucosa, gingiva, and the underlying periosteum both in the labial and lingual regions [ 7 , 8 ]. Typically found in the maxillary labial/buccal, mandibular labial, and mandibular lingual areas, the frenum's attachment level and morphological shape can vary [ 9 ].…”

“…One positive function of the frenum is its role in stabilizing the upper and lower lips as well as the tongue in the floor of the mouth [ 9 ]. It is regarded as a residual structure that remains after a certain process, representing the connection between the upper lip's tubercle and the palatine papilla [ 8 ]. Initially, the frenal attachment is higher in the middle of the attached gingiva, but as development progresses, it shifts more apically below the mucogingival junction [ 10 ].…”

Maxillary Frenulum and “Lip Tie”: What Parents Understand

“…The maxillary frenulum arises as a posteruptive remnant of embryonic tectolabial bands 2 and may provide stability to the lip 3 . The structure comprises tight connective tissue interwoven with occasional skeletal muscle fibers 4 . These muscle fibers originate from the orbicularis oris muscle of the upper lip 5 ; there are no major vessels within the maxillary frenulum 4 .…”

“…4 These muscle fibers originate from the orbicularis oris muscle of the upper lip 5 ; there are no major vessels within the maxillary frenulum. 4 The size of the frenulum and its insertion locations are variable among individuals. 6 Although maxillary frenula are almost universally present and are considered normal structures, the point at which they can be classified as tethered, known colloquially as "lip tie" (LT), remains unclear.…”

“…The structure comprises tight connective tissue interwoven with occasional skeletal muscle fibers 4 . These muscle fibers originate from the orbicularis oris muscle of the upper lip 5 ; there are no major vessels within the maxillary frenulum 4 . The size of the frenulum and its insertion locations are variable among individuals 6 …”