Understanding Hair Anatomy: Cuticle, Cortex, Medulla, Cortical Fusi, Ovoid Bodies, and Pigment Granules

Have you ever wondered what makes up the structure of your hair? The intricate anatomy of our hair strands comprises several distinct components, each playing a unique role in the appearance and health of our hair. In this article, we will explore the essential elements of hair anatomy: the cuticle, cortex, medulla, cortical fusi, ovoid bodies, and pigment granules. Understanding these components will not only deepen your knowledge of hair but also help you identify them and comprehend their significance. So, let's dive in!

The Cuticle:

The cuticle is the outermost layer of the hair shaft, serving as a protective barrier. Composed of transparent, overlapping scales, it resembles the shingles on a roof. The cuticle's primary purpose is to safeguard the inner structures of the hair, such as the cortex and medulla, from damage caused by external factors like heat, chemicals, and UV radiation. It also helps retain moisture within the hair shaft.

Identifying the Cuticle: to observe the cuticle, pluck a single strand of hair and examine it closely. The cuticle will appear as a thin, colourless layer consisting of overlapping scales. Under a microscope, the scales may resemble the appearance of fish scales or roof tiles.

The Cortex:

The cortex lies beneath the cuticle and constitutes the majority of the hair strand's structure. It is responsible for the hair's strength, elasticity, and colour. The cortex contains long chains of proteins known as keratin, which give hair its characteristic strength and structure. The natural pigment called melanin is also found within the cortex, determining the colour of the hair.

Identifying the Cortex: to identify the cortex, examine a cross-section of a hair strand. The cortex will appear as a dense, fibrous region occupying the central portion of the hair shaft. It gives the hair its thickness and provides elasticity when stretched gently.

The Medulla:

The medulla, also known as the pith, is the innermost layer of the hair shaft. However, not all hair types possess a medulla, as its presence varies among individuals and even within different hair strands of the same person. The function of the medulla remains somewhat unclear, although it is believed to contribute to the overall strength and flexibility of the hair.

Identifying the Medulla: to identify the medulla, examine the center of a hair strand. It may appear as a hollow, cylindrical structure, often filled with air or a softer, less organized tissue compared to the cortex. In some cases, the medulla may be absent, resulting in a hair strand without a visible innermost layer.

Cortical Fusi:

Cortical fusi are small, irregularly shaped air spaces or gaps found within the cortex of the hair shaft. These structures are relatively rare and can be present in varying densities among individuals. Cortical fusi are believed to be remnants of cellular structures that didn't fully compact during hair development.

Identifying Cortical Fusi: to identify cortical fusi, examine the cross-section of a hair strand. They may appear as small, irregularly shaped air bubbles within the cortex. Under a microscope, they may resemble small voids or irregularly shaped spaces within the hair shaft.

Ovoid Bodies:

Ovoid bodies, also known as egg-shaped bodies or oval bodies, are small structures found within the cortex of hair strands. These bodies are thought to be remnants of pigment cells or melanocytes, which are responsible for producing melanin—the pigment that gives hair its colour. Ovoid bodies are commonly found in gray or white hair, as the reduction in melanin production leads to their accumulation.

Identifying Ovoid Bodies: to identify ovoid bodies, it is best to examine a cross-section of a hair strand under a microscope. They typically appear as small, oval-shaped structures located within the cortex. Ovoid bodies are often seen as round or elongated shapes that may vary in size. In hair with a higher concentration of ovoid bodies, the presence of these structures can contribute to the appearance of a lighter or grayer hair colour.

Pigment Granules:

Pigment granules, also known as melanin granules, are responsible for providing colour to our hair. Melanin, produced by melanocytes in the hair follicles, exists in two primary forms: eumelanin (which produces brown and black hues) and pheomelanin (which produces red and yellow hues). The distribution and density of these pigment granules determine the specific shade of our hair colour.

Identifying Pigment Granules: to identify pigment granules, examine a hair strand under a microscope. Depending on the colour of the hair, you will observe different types and densities of granules. In dark hair, such as brown or black, you will see larger and denser eumelanin granules, whereas in lighter hair, such as blond or red, the granules will be smaller and less densely packed. The distribution of pigment granules contributes to the overall colour appearance of the hair strand.

Tips for Identification:

• Sectioning hair samples: For a clearer view, consider cross-sectioning hair samples. This technique involves cutting hair strands at various angles to expose the inner structures, providing a more comprehensive understanding of ovoid bodies and pigment granules.

• Utilize a microscope: To observe these microscopic structures, a microscope with sufficient magnification is essential. Higher magnification allows for a more detailed examination of ovoid bodies and pigment granules. 

• Seek professional assistance: If you're unable to identify ovoid bodies or pigment granules accurately, consult a trichologist or a hair care professional. These experts specialize in the study of hair and can provide valuable insights into the unique characteristics of your hair.

Understanding the different components of hair anatomy, empowers us to make informed choices when it comes to hair care and styling. Whether it's protecting the hair shaft (cuticle), providing strength and colour (cortex), contributing to flexibility (medulla), observing unique irregularities (cortical fusi), or producing melanin and providing colour (ovoid bodies and pigment granules), each component plays a vital role in defining the properties of our hair anatomy. Embrace the wonders of your hair and continue exploring the remarkable world of hair anatomy!