Muscle, adipose, and connective tissue variations in intrinsic musculature of the adult human tongue.

The purpose of this investigation was to identify the composition and organization of lingual tissues underlying the histostructural and biomechanical functions of the adult human tongue. The small-scale structures of three intrinsic muscle regions, their principal cells, structural complexities, and differences in underlying tissue composition were compared to other skeletal muscle systems and the results discussed in relation to lingual morphology. Analysis of pixel color distributions determined the percent area concentration of each stained tissue component. Results indicated that muscle content increased from anterior to posterior (p <.0001). Greater adipose (p =.005) and connective tissue (p <.002) concentrations occurred in anterior regions. Dense collagen sheaths and elastic fibers found anteriorly occurred with less magnitude in medial and posterior sites. The unique elastin, collagen, and adipose connective tissue distributions found in intrinsic sampling sites are discussed in terms of understanding lingual biomechanics in both normal and pathologic states.