title: Histochemical characterization of masseter muscle fibres in a biopsy study of normal young women.
abstract: Muscle fibres from biopsies of the anterior part of the masseter muscle (pars superficialis) were histochemically characterized in 13 healthy female students. They were 21-28 yr old with a full complement of teeth, and normal facial and occlusal relations. Before surgery, normal masseter muscle function was demonstrated by bite-force measurements and recordings of electromyographic activity. After staining for myosin ATPase activity, the relative mean areas of muscle fibres were: type I 82.9%, type IM 9.5% and type II 8.3%. The intraindividual (18-155% of mean) and interindividual (0-216% of mean) variation of the fibre size was large. The type I fibres had the largest diameter (10-80 microns, mean: 39 microns), the type II fibres (6-47 microns, mean: 21 microns) and the IM fibres (8-54 microns, mean: 28 microns) the smallest. The biopsy technique and the histochemical characterization will be suitable for reference in women with functional changes or diseases of the masseter muscle.
authors: Department of Oral Function and Physiology, School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Denmark.
authors: A
authors: A
authors: Tuxen
authors: M
authors: M
authors: Bakke
authors: B
authors: B
authors: Kenrad
mesh_terms: D000328:Adult; D001706:Biopsy; D005260:Female; D006651:Histocytochemistry; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008406:Masseter Muscle / Q000201:enzymology / Q000648:ultrastructure*; D009210:Myofibrils / Q000201:enzymology / Q000648:ultrastructure; D009218:Myosins / Q000032:analysis
chemical_list: D009218:Myosins