Hearing Instrument Specialist Practice Exam 2026 - Free Hearing Instrument Specialist Practice Questions and Study Guide

The lateral one-third of the external auditory canal is primarily composed of skin-covered cartilage. This anatomical structure starts at the pinna and extends inward, maintaining a flexible and resilient nature due to the cartilage that supports it. The skin in this region is also lined with glands that produce earwax, or cerumen, which helps to protect the canal from debris and infection.

In contrast, as one moves deeper into the external auditory canal, the tissue transitions from cartilage to bony structures in the inner two-thirds. This cartilaginous composition in the lateral third allows for a certain degree of movement and adaptability, which is important as it occasionally has to accommodate the insertion of ear devices or the movement of the jaw during activities like chewing.