Unable to hear
Why we are unable to hear while yawning?
T. Subbiah Ganesh
Chennai, Tamil Nadu
During yawning, several things happen together concurrently causing a general contraction of several muscle groups associated with mouth, throat, face, diaphragm, larynx, and palate. Yawning also accompanies stretching of muscles in the neck.
Some physiologists hold the view that different physiological mechanisms control respiration and yawning.
Yyawning has other important temporary physiological and anatomical effects, such as, increase in blood pressure and heart pulsation rate.
As a result of the stretching and contraction of several muscles of the face, jaw and throat, the muscles of the middle ear get constricted.
This leads to a chain of muscular events that lead to the reduction of sound intensity reaching the tympani.
The pressure on the eustachian tubes, running from the middle ear to the throat, by the flexing muscles during yawning can contribute to the reduction of the volume of sound we hear.
Similar effects of reduced hearing are experienced during the infection and inflammation of the fauces.
Similarly, the muscular contractions can influence the transmission of sound by the ossicular chain responsible for hearing.
These effects, in addition to the partial blocking of the air path of the ear, reduce the sensitivity of the ears.
Further, the muscular contraction exerts pressure on the nerves served into the ears, temporarily rendering them somewhat ineffective during yawning.
Some people sense some ringing or roaring sound during yawning because of this temporary alteration of the condition of the auditory nerves.
In fact, we do not completely stop hearing during yawning; but the loudness reduces. This condition is relieved immediately after the process of yawning is completed.
DR. H. K. SAHU
SCIENTIFIC OFFICER, IGCAR
KALPAKKAM, TAMIL NADU
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