EN2.{3,5} | Otoscopy Tuning Fork Testing and Tympanic Membrane Assessment — Summary & Reflection

KEY TAKEAWAYS

Otoscopy technique: pinna traction upward-backward (adults), largest comfortable speculum, inspect EAC then TM landmarks systematically (pars tensa, pars flaccida, handle of malleus, short process, umbo, light reflex in antero-inferior quadrant). Central perforation = CSOM safe (tubotympanic); attic/marginal perforation = CSOM unsafe (atticoantral, cholesteatoma). TM diagram: circle with malleus handle, mark perforation site and type. Tuning fork tests use 512 Hz standard frequency. RINNE: negative (BC > AC) = conductive loss; positive (AC > BC) = normal or SNHL. WEBER: to the AFFECTED ear = conductive loss (occlusion effect); to the BETTER ear = SNHL. ABC: reduced = SNHL (cochlear damage). Combined patterns — conductive: Rinne NEGATIVE affected side + Weber to affected + normal ABC; SNHL: Rinne POSITIVE affected side + Weber to BETTER side + reduced ABC. Exception: false-negative Rinne (dead ear) — BC vibration crosses to contralateral cochlea, mimicking conductive loss on the dead side; suspect when Rinne negative but TM normal. Pneumatic otoscopy (Siegle's speculum) assesses TM mobility — reduced = middle ear fluid; unrestricted = perforation.

REFLECT

The tuning fork test interpretation rules are some of the most reliably confused facts in MBBS ENT — which makes them some of the most reliably examined. Before your next clinical or OSCE session, test yourself without notes: what does Rinne POSITIVE mean (not just the words — the mechanism)? Why does Weber go to the affected ear in conductive loss but the better ear in SNHL? If you cannot explain the mechanism, not just state the rule, you will invert the rule under examination pressure. The reflection task is this: on a blank piece of paper, write out all three test patterns for normal, CHL, and SNHL from memory, then check against this SDL. Identify any pattern you got wrong and trace the mechanism until the reason for each result is clear — that is the level of understanding that survives an OSCE.