title: Fibre type proportions of the buccinator muscle in clinically normal adult dogs.
abstract: In order to provide normal morphological data and reference values for fibre type proportions, against which changes due to facial nerve paralysis or primary facial muscle myopathies can be compared, a histological and histochemical study was carried out on the buccinator muscle of clinically normal adult dogs. Using myosin adenosine triphosphatase under acidic pre-incubation (pH 4.3) conditions, three histochemical fibre types--1, 2A and 2C were recognised. There was no significant difference in mean diameter between left- and right-sided buccinator muscle samples for type 1 versus 2. Mean diameters of fibre types were: type 1, 27.02 +/- 6.61 microns and type 2, 29.05 +/- 7.75 microns. The histographical distribution of fibre type diameters was unimodal. The buccinator muscle had a type 2 fibre predominance with a mean type 1 to type 2 ratio of 32:68. The number of fibres with internal nuclei was less than or equal to 1 per cent, atrophy-hypertrophy factors typically were less than or equal to 200, and variability coefficients approximated 250. Muscle spindles were not observed in any muscle sample.
authors.affiliation: Neuromuscular Research and Diagnostic Laboratory, Scott-Ritchey Research Program, College of Veterinary Medicine, Auburn University, Alabama 36849.
authors.forename: K G
authors.initials: KG
authors.lastname: Braund
authors.forename: J R
authors.initials: JR
authors.lastname: Mehta
authors.forename: K A
authors.initials: KA
authors.lastname: Amling
mesh_terms: D000818:Animals; D004285:Dogs / Q000033:anatomy & histology*; D005152:Facial Muscles / Q000033:anatomy & histology*; D006651:Histocytochemistry; D009218:Myosins; D012016:Reference Values
chemical_list: D009218:Myosins