Dehiscence of anterior wall of the external auditory canal cause infection in the parotid gland
**Core Concept**
Dehiscence of the anterior wall of the external auditory canal creates an abnormal communication between the external auditory canal and the parotid gland, leading to the potential for infection spread. This anatomical defect is known as the "fissula ante fenestram" or "Bill's bar".
**Why the Correct Answer is Right**
Infection from the external auditory canal can spread to the parotid gland through this dehiscence, which is a result of the incomplete bony separation between the external auditory canal and the parotid gland. The parotid gland is a complex structure that contains the facial nerve, and infection in this gland can lead to serious complications, including facial paralysis.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the dehiscence of the anterior wall of the external auditory canal does not typically lead to infection in the middle ear.
* **Option B:** This option is incorrect because the infection is not spread through the Eustachian tube, which connects the middle ear to the nasopharynx.
* **Option C:** This option is incorrect because the infection is not directly related to the spread of infection from the external auditory canal to the temporal lobe.
**Clinical Pearl / High-Yield Fact**
It is essential to note that the parotid gland has a complex anatomy, and surgical procedures in this area require great care to avoid damaging the facial nerve. Infections in this gland can lead to serious complications, including facial paralysis, and require prompt medical attention.
**Correct Answer:** A.