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Chapter 9 — 5
Fig. 9.5
If equalisation does not occur, the middle ear space
is partly filled with blood, tissue fluid and swollen mucosa.
Clinical Features
A sensation of
pressure
is the first symptom of damage to the ear. This pressure sensation may
develop into
pain
, which is usually severe, sharp and localised to the affected side. It increases
as the diver descends, unless he equalises the middle ear spaces.
If the diver continues descending
until the
ear drum ruptures
, he
will experience relief of the
pressure or pain, followed by a
cold feeling
in the ear. This is due
to the sea-water which enters the
middle ear space, cooling the bone
and tissues near the balance organ.
Thermal
currents
may
be
produced within the balance
organ, causing stimulation and
dizziness. Fluid may also be felt
trickling down the throat, after
running down the Eustachian tube
from the middle ear space.
Fig. 9.6
Large perforation of
the ear drum from a
single dive to 8 metres
without adequate
equalisation.