A blast injury presenting with tinnitus, vertigo, and blood in the ear indicates possible damage to which structure?

When evaluating a blast injury characterized by tinnitus (ringing in the ears), vertigo (a sensation of spinning or loss of balance), and blood in the ear, the involvement of the tympanic membrane is particularly significant. The tympanic membrane, commonly referred to as the eardrum, can be compromised during a blast due to the rapid changes in pressure and the force of the blast wave.

Damage to the tympanic membrane can lead to bleeding and can also disrupt normal auditory function, leading to tinnitus and vertigo as the inner mechanisms of the ear may be affected as well. This membrane serves as a barrier between the external ear canal and the middle ear; when it is ruptured or perforated, it may allow blood from the middle ear to present in the external ear canal.

While other structures such as the inner ear, auditory nerve, and external ear could also sustain damage in a blast scenario, the specific symptoms presented—especially the presence of blood—are most closely associated with injury to the tympanic membrane. That is why damage to this structure can lead to the symptoms observed in this case.