Everything to Know About Hair Root Anatomy

Rohit Kushwah

Medically Reviewed By Dr. Aarti Nehra

Hair root is located on your skin and goes down deeper into the skin layers. Hair follicles connected to the sebaceous glands surround hair roots. Each hair follicle is attached to the arrector pili, a tiny muscle that makes the hair stand up. Strong hair roots influence hair growth. What is hair root and how to make it strong are explained in this article. Read on to delve into the hair root anatomy.

Anatomy of Hair Root

To understand the anatomy of the hair root and how to strengthen hair roots, the other parts linked to the hair root have to be explained. Hair root is surrounded by hair follicle in the skin and it extends upwards into hair shaft. 

Hair Follicle

The magic of hair growth begins at the hair follicle. Nourishing the hair follicle results in stronger and thicker hair strands. The hair follicle is made up of

  • Papilla: Papilla is a vital structure of the hair follicle. It is loaded with blood vessels. The role of the papilla is of prime importance as it supplies the essential nutrients and oxygen to the hair enhancing the growth and strength of the hair. It provides the necessary conditions for hair proliferation and is hence considered the lifeblood of the hair. 
  • Bulb: It is an onion-shaped structure found at the base of the hair follicle. The cells dividing actively to form the hair shaft are in the bulb. The cells divide to create new cells that are pushed upwards, which eventually form the hair shaft.
  • Sebaceous glands: Sebaceous glands are found on the upper layer of the hair follicle. These glands are responsible for the secretion of sebum, the natural oils that keep the hair hydrated, condition it, and maintain elasticity. Sebum forms a protective layer around the hair and prevents it from drying and becoming brittle. This strengthens the hair and inhibits hair breakage.

Hair Shaft

The hair shaft that extends beyond the surface of the skin has three layers

  • Cuticle: The Cuticle located at the outermost layer of the hair shaft consists of scale-like cells that protect the inner layers of the hair from damage. The main role of the cuticle is to protect the medulla and cortex from damage. A healthy cuticle makes the hair shiny.
  • Cortex: This is the center layer of the hair shaft and houses the structural protein of the hair, i.e., keratin. Keratin makes the hair strong and flexible. Since pigments are found within the cortex, this layer determines the hair color as well.
  • Medulla: Medulla lies in the innermost layer of the hair shaft. The role of the medulla is not particularly defined as it may vary with individuals and between hair strands of the same individual.

Hair Root Sheath

Hair root sheath has the pivotal role of protecting the hair within the hair follicle. It is mainly made of the inner root sheath and the outer root sheath, which have individual roles to play.

  • Inner Root Sheath: The inner root sheath provides an extra protective layer to the hair shaft. It helps shield the hair structure from external damage and facilitates its extension through the hair follicle to form a hair strand.
  • Outer Root Sheath: The outer root sheath covers the hair follicle and holds it within the skin. It provides stability to the growing hair and prevents it from being easily pulled out. The bulb located at the base of the hair follicle gets the nutrients and oxygen required for hair growth from the outer root sheath, consisting of several blood vessels. 

The hair is pushed upwards as the cells divide and differentiate within the hair follicles with the help of the outer root sheath to form the hair shaft. This root sheath also determines the stage of hair growth, i.e., the anagen, catagen, or the telogen stage.

The hair follicle, hair shaft, and hair root sheath play a coordinated role in the hair growth and appearance of the hair.


The hair root is not strong by itself. A healthy hair follicle and hair shaft eventually create healthy hair roots. They work in coordination to give you a thick tuft of shiny and strong hair to enhance your looks.


Rohit Kushwah


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