The
therapeutic aspects of talking, shouting,
singing,
laughing,
crying, sighing and
yawning
Harry Campbell
Northwest London
Hospital
Yawning
It is difficult to describe accurately this
act. A deep and prolonged inspiration is taken
through the mouth and nose, the mouth being
widely opened and the nares dilated. The opening
of the mouth is effected by a strong tonic
contraction of the depressors of the lower jaw
and by the extension of the head and consequent
elevation of the upper jaw.
At the same time the limbs and trunk are
stretched. There is, in short, a widespread
tonic contraction of the muscle system. This
continues and indeed reaches its climax during
the expiratory portion of the act, the month
being kept open till towards the end of it. The
expiratory blast is directed solely through the
mouth owing to the elevation of the soft palate,
and the vocal cords approximate, a
characteristic sound being produced in the
larynx, while there is a peculiar contraction of
the muscles at the back of the throat the nature
of which I do not understand.
There can be little doubt that one of the
objects of yawning is the exercise of muscles
which have been for a long time quiescent, and
the acceleration of the blood and lymph flow
which has in consequence of this quiescence
become sluggish.
Hence its frequency after one has remained
for some time in the same position -e.g., when
waking in the morning. Cooperating with this
cause is sleepiness and the shallow breathing
which it entails. This factor, as well as
muscle-quiescence, is apt to attend the sense of
boredom which one experiences in listening to a
dull a sermon.
Hence it is that the bored individual is apt
to yawn. As in the case of sighing, the deep
breath which accompanies the act of yawning
compensates for the shallow breathing which is
so apt to excite it. I am unable to offer any
explanation of the yawning-or, rather,
gaping-which is induced by exhaustion from want
of food. This mere gaping is, however, quite
distinct from yawning, which is a much more
complex phenomenon. Allied to yawning is a
modification of the breathing which is apt to
occur during sleep.
A deep breath is taken more or less
suddenly, and this is followed by a long drawn
out expiration with probbly closed glottis and a
gronning sound.This kind of breathing has
certainly some physiological import, but what it
is I cannot say.
