Mastoid infection which erodes through the outer cortex of bone results in –
**Core Concept**
Mastoiditis is an infection of the mastoid process, a bony structure behind the ear. The outer cortex of the mastoid bone is a critical area that, when eroded, can lead to serious complications. The mastoid cortex is a thin layer of bone that is susceptible to erosion by bacterial infection.
**Why the Correct Answer is Right**
When a mastoid infection erodes through the outer cortex of the bone, it can lead to a condition known as a mastoid fracture or a cortical mastoidectomy. This is because the outer cortex is no longer intact, allowing for the potential spread of infection to surrounding structures. The infection can also lead to the formation of a sequestrum, a piece of dead bone that is separated from the surrounding living bone. This can occur due to the infection causing necrosis (death) of the bone tissue.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because a cortical mastoidectomy is not a type of mastoiditis, but rather a surgical procedure to remove infected bone tissue.
**Option B:** This option is incorrect because a mastoid fracture is not a type of mastoiditis, but rather a complication that can arise from the erosion of the outer cortex of the mastoid bone.
**Option C:** This option is incorrect because a sequestrum is not a type of mastoiditis, but rather a complication that can arise from the erosion of the outer cortex of the mastoid bone.
**Clinical Pearl / High-Yield Fact**
In cases of mastoiditis, it is essential to monitor for signs of erosion through the outer cortex of the bone, as this can lead to serious complications such as a mastoid fracture or sequestrum formation.
**Correct Answer:** C. Sequestrum formation.