| Description |
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The presence of fresh blood within the middle ear gives the tympanic membrane a red coloration.
The presence of old blood within the middle ear gives the tympanic membrane black or gunmetal blue coloration.
Over time, as the hemoglobin degrades, the fluid assumes a brownish color and the tympanic membrane takes on a chocolate brown color (chocolate eardrum.
Blood appears to be well tolerated by the middle mucoperiosteum, and over time the blood is gradually cleared from it with the assistance of the ciliated epithelial cells lining the middle ear and the Eustachian tube.
In rare cases (usually associated with inflammation or prolonged stasis), cholesterol crystals derived from the degenerating erythrocytes may give rise to a cholesterol foreign body type of granulomatous reaction (cholesterol granuloma). |
