Vol.102 No.7 contentsPRACTICA OTO-RHINO-LARYNGOLOGICA
Vol. 102 No. 7 July 2009
Functional Role of the Stapedius Muscle
Tetsuaki Kawase
(Tohoku University Graduate School of Biomedical Engineering, Tohoku University
Graduate School of Medicine, Tohoku University Hospital)
The stapedius muscle constitutes one of the efferent feedback pathways to the auditory periphery, which can be elicited by sound in either ear. Contraction of the stapedius muscle causes attenuation of the low frequency component of the input signal by increasing the stiffness of the ossicular chain. The effects of the acoustic reflex have been investigated for many years and a number of hypotheses have been proposed. Two of these hypotheses are: (1) that this reflex helps to protect the ear from acoustic injuries and (2) that it aids in the control of masking. However, there is still significant controversy as to its functional significance. In the present paper, possible functional roles of the stapedius muscle are discussed based on the physiological properties of the acoustic reflex of this muscle.
Key words :stapedius muscle, masking, physiology