3D Genial Tubercle Anatomic Considerations in Genioglossus Advancement Surgery

Abstract

AbstractObjectiveTo qualitatively describe variation in morphology of the genial tubercle and quantify the spatial relationship between the tubercle and genioglossus muscle.Study DesignCase series.SettingCadaver dissection.MethodsSegmental 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.ResultsThe 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.ConclusionThe 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.