What is the function of the medulla in the hair shaft?

The medulla is the innermost layer of the hair shaft, but its exact function remains not entirely understood. While some research suggests it may play a role in the overall structure of the hair and potentially contribute to hair pliability, its functions do not have a definitive understanding in the scientific community. It may be more prominent in thicker hair types, but the specifics of its contribution to hair health, strength, or pigmentation are still being studied.

In contrast, the other options focus on functions that are attributed to different parts of the hair or the hair follicle itself. For instance, insulation and protection are roles typically associated with the outermost layer of the hair shaft, known as the cuticle. Hair pigmentation is primarily due to melanin produced in hair follicles, not the medulla. Anchoring the hair follicles is primarily the role of the dermal papilla and surrounding structures in the scalp, not the medulla itself. Thus, the lack of a clearly defined role for the medulla supports that its function is indeed not fully understood.