Genial tubercles: Morphological study of the controversial anatomical landmark using cone beam computed tomography

Unique anomalous in the main mental foramen opening, mandibular canal pathway, and size and shape of genial tubercles: A case report

This clinical report presents a unique and previously unreported case of anatomical variations in the mandible, specifically involving the main mental foramen (MF), the mandibular canal (MC), and genial tubercles (GTs). The case involves a 21-year-old male seeking dental implant rehabilitation. The patient exhibited an unusual lingual exit path of the main left MF through the lingual cortical bone, with the MC following an anterior lingual direction along a lingual groove before exiting through the labial cortical bone between the apexes of the left canine and first premolar. Additionally, the patient displayed excessive enlargement and rare shape of the GTs. These rare anatomical findings presented challenges in dental implant planning. This case report emphasizes the importance of advanced imaging techniques like cone-beam computed tomography (CBCT) in evaluating mandibular structures for precise treatment planning and highlights the significance of understanding anatomical variations to prevent complications in dental procedures.

3D Genial Tubercle Anatomic Considerations in Genioglossus Advancement Surgery

OBJECTIVE

To qualitatively describe variation in morphology of the genial tubercle and quantify the spatial relationship between the tubercle and genioglossus muscle.

STUDY DESIGN

Case series.

SETTING

Cadaver dissection.

METHODS

Segmental sections of the mandible, with muscular attachments intact, were harvested from 18 fresh cadaver heads. Three-dimensional laser scans, with a resolution of 0.025 mm, were taken of each specimen with muscle attached and repeated after muscle removal. The genioglossus muscular attachment was measured relation to bony landmarks.

RESULTS

The morphology of the genial tubercle varied, with anywhere from 1 large spine to 4 individual spines. However, all specimens had a distinguishable superior portion of the tubercle, where the genioglossus attached, and an inferior portion, where the geniohyoid attached. The height of the superior tubercle (ST) was 6.1 mm (95% confidence inerval [CI]: 5.7-6.5). The height of the genioglossus muscle above the peak amplitude of the ST was 4.3 mm (3.8-4.9), but only 2.5 mm (2.0-3.0) below. On average, 64.4% (58.6-70.2) of the height of the genioglossus muscle attachment was above the peak. Overall, 19.5% (14.1-25.0) of the muscle surface area extended beyond the boundaries of the tubercle.

CONCLUSION

The genioglossus muscle attachment originates from the superior genial tubercle, which has a variable topography and amplitude. However, the muscle is not centered on the spines-more of the muscular fibers attach above the spine as compared to below. This new data may explain the genioglossus advancement "miss rate"-failure to advance muscle on initial osteotomy-of 39-78% reported in the literature.

Morphometric aspects and proposal of a new classification of genial tubercles in cone-beam computed tomography in a Brazilian population

Objective

This study evaluated epidemiological and morphological aspects of genial tubercles (GTs) using cone-beam computed tomography (CBCT).

Methods

This retrospective, observational and cross-sectional study evaluated 276 tomographs of adult dentate individuals (18–69 years). The presence and absence of GTs were evaluated, and in cases in which this structure was observed, linear measurements (length, height, and width), and anatomical distances. In addition, a GT classification was proposed based on the presence, number, and location of the tubercles.

Results

Of the 276 CT scans, 28 (10.14%) had absence of GTs and in 248 CT scans GTs were present, of which 42 (57.5%) were from females and 106 (42.5%) from males. Regarding the number of GTS, the most prevalent variant was the two-tubercle-variant (143, 57.7%), followed by the presence of a single tubercle (n = 62, 25.0%), 3 tubercles (n = 40, 16.1%) and 4 tubercles (n = 3, 1.2%). The most prevalent classification was IIIA (n = 96, 38.7%), followed by IIIB (n = 60, 36.3%), IIA (n = 53, 21.4%) and IIB (n = 9, 3.6%).

Conclusion

A prevalence of GT of approximately 90% was observed, with two GTs per exam as the most frequent finding. Men had a longer mean GT length compared to women. Female individuals exhibited a shorter distance from the base of the GT to the base of the mandible.

Comparison of Genial Tubercule Anatomy Based on Age and Gender

Objective

In our study, it was aimed to determine whether there were differences in genial tubercle dimensions depending on age and gender.

Methods

In this study, 220 cone beam computed tomography (CBCT) images of patients (110 female and 110 male) between the ages of 20-80 years were obtained from the archive of İzmir Katip Çelebi University Faculty of Dentistry. All patients were divided into decade groups according to their age, and each decade group was divided into two subgroups according to gender. The genial tubercle was defined radiologically using axial, coronal and sagittal sections as well as 3D reconstruction image with NNT software program. Sagittal, vertical and horizontal dimensions of the genial tubercle were measured and statistically analyzed.

Results

There was a weak negative correlation between age groups and vertical values (r=-0.142; p=0.036) whereas the correlation coefficients between age groups and sagittal and horizontal values were not statistically significant (r=-0.043; p=0.530 and r=-0.039; p=0.563). There was a strong positive correlation between vertical and sagittal values in men (r=0.705, p<0.001) and women (r=0.714, p<0.001) in the whole group. There was a weak positive correlation between horizontal and sagittal, horizontal and vertical values in men (r=0.362, p<0.001; r=0.231, p<0.001) and women (r=0.304, p<0.001; r=0.257, p=0.007) in the whole group.

Conclusion

The vertical and horizontal dimensions of genial tubercle of men were higher than that of women. As the age of the patients increased, a decrease in the vertical values of the genial tubercle was observed.