What are the three main layers of the hair shaft?

• A. Root, cortex, medulla
• B. Cuticle, cortex, and medulla
• C. Follicle, cortex, cuticle
• D. Shaft, cuticle, medulla

Answer: (B)

The hair shaft is built in three layers from outside to inside: cuticle, cortex, and medulla. The cuticle is the thin, protective outer layer made of overlapping cells that lie flat to form a smooth surface and help control moisture and shine. The cortex sits beneath, forming the thick, fibrous middle layer where most strength, elasticity, and pigment reside. The medulla is the central core that may be absent in very fine hair but provides additional structure in thicker hair.

This ordering—cuticle on the outside, followed by cortex, then medulla—is why the correct answer is the one that lists cuticle, cortex, and medulla. The other options mix in structures that aren’t layers of the hair shaft (for example, growth-related parts like the root or follicle, or use shaft as a layer rather than the whole strand), so they don’t describe the real layered makeup of the hair shaft.