Bright red blood in the left external auditory canal would indicate rupture of which structure?

• A. Pain in both ears
• B. Clear fluid in canal
• C. Bright red blood in the left external canal
• D. Absence of hearing in the left ear

Answer: (C)

Blood in the external auditory canal is a direct sign that the barrier between the middle ear and the canal—the tympanic membrane—has ruptured. When the tympanic membrane tears, blood from the vessels in the middle ear can escape into the canal, often appearing bright red because it is fresh. This is more specific than other findings because it ties a visible canal finding to a structural break in the membrane that separates the external ear from the middle ear. Other signs, like pain in both ears, clear fluid in the canal, or absence of hearing, can occur with many different ear conditions and do not point as clearly to a tympanic membrane rupture.