The
adenoid is a group of lymphoid tissue at the roof of the pharynx .Present
at birth it hypertrophies between the ages 4 and 14 and atrophies
at puberty . In young children overgrowth of this lymphoid tissue
in the nasopharynx with or without enlargement of the tonsils may
obstruct the respiratory passage. Obstruction to the respiration through
the nose makes mouth breathing more or less obligatory .In order to
breathe as the child has to keep its mouth open the hard palate and
alveolar arch remain habitually out of contact with dorsm of the tongue
. Lacking pressure from the tongue the children develop with an abnormally
high arch palate .The hardpalate becomes narrowed laterally .The projecting
alveolar process cannot afford sufficient room for the permanent teeth
.They are therefore crowded ; irregularly set and overhang those in
the lower jaw . The protruding upper incisors compel the child to
keep the mouth open .As a result the child's saliva dribbles from
the open mouth during sleep .The facial surfaces of the maxillae become
pinched together .Therefore the nasal cavities and the maxillary air
sinuses become narrowed resulting in altered voice and accents with
or without nasal twang .The upper lip is drawn up still further exposing
the front upper teeth resulting in dryness of the upper lip and collection
of tartar on the upper teeth .By drooping of the lower jaw the face
is lengthened .The whole expression of the child is highly characteristic
suggesting vacuity and inattention .This is due to the deafness so
often associated with the obstruction of the nose and of the Eustachian
tubes .The deafness and inattentiveness interferes with the learning
.Hence the child grows with lowered intelligence and understanding
.These children may lag behind their contemporaries in the school
and may even fail in the school examinations .
