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Preferential denervation of the adductor muscles of the equine larynx II: Nerve pathology
Author(s) -
DUNCAN I. D.,
REIFENRATH P.,
JACKSON K. F.,
CLAYTON M.
Publication year - 1991
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.1991.tb02729.x
Subject(s) - adductor muscles , denervation , anatomy , recurrent laryngeal nerve , medicine , larynx , horse , biology , paleontology , thyroid
Summary The terminal branches of the recurrent laryngeal nerve (RLN) of three normal ponies and six horses with sub‐clinical laryngeal disease were examined qualitatively and quantitatively in an attempt to explain the preferential denervation of the laryngeal adductor muscles in the neuropathy of idiopathic laryngeal hemiplegia (ILH). The myelinated fibre spectra of all the motor nerve fibres in the left and right abductor and adductor branches of the RLN in three normal ponies were measured. The density of myelinated fibres was also calculated. There was no significant difference between the larger group of myelinated fibres in the adductor or abductor branches. In the six horses with laryngeal hemiparesis, however, there was a marked preferential loss of the medium/large size myelinated fibres in the left adductor branch, although nerve fibre densities were not significantly different. While no simple morphometrical feature was found to explain the selective muscle denervation, the greater loss of large diameter myelinated fibres in the adductor branches confirms the earlier observation of adductor muscle susceptibility in the neuropathy of ILH.