Scalp: Anatomy, Functions and Disorders

Embark on a journey to discover the scalp and its integral role in our overall well-being and its influence on hair health and appearance.

Introduction to Scalp

The scalp is the skin-covered region on the top of the head. It extends from the forehead to the lower back portion of the neck. It is an essential part of the integumentary system, which also includes the skin and hair.

The scalp serves as a protective layer for the underlying skull and brain. It plays a crucial role in maintaining the health and appearance of our hair.

Let’s learn about the importance of Scalp Health.

Importance of Scalp Health

The scalp is a very important region in the human head. So, to understand its health we will divide it into various points:

Hair Growth and Appearance– The condition of our scalp directly impacts the growth and appearance of our hair. A healthy scalp helps hair follicles to produce hair, promoting strong and shiny hair growth. Conversely, an unhealthy scalp can lead to hair loss, thinning, or brittle hair.
Blood Circulation– A well-nourished scalp with good blood circulation ensures that hair follicles receive essential nutrients and oxygen. It is vital for hair growth and maintenance.
Preventing Hair and Scalp Disorders– A scalp may contain disorders such as → dandruff, psoriasis, seborrheic dermatitis, and fungal infections. Regular scalp care and hygiene are crucial in preventing these conditions. We will discuss the other scalp disorders, later in the upcoming parts of the article.
Protecting the Skull and Brain– The scalp acts as a natural barrier. It protects the skull and brain from external forces and potential injuries.
Psychological Well-being: The appearance of our hair and scalp can significantly impact our self-esteem and confidence. A healthy scalp contributes to better emotional well-being.

Therefore, scalp health is essential for the well-being of humans. Now, we will discuss the layers of the scalp, which include skin, Periosteum and many more.

Layers of the Scalp

Layers are an essential part of our anatomy. It serves as a protective covering for the skull and provides support for the hair follicles. It consists of several distinct layers. Each plays a crucial role in safeguarding the brain and also facilitating various physiological functions. Let’s delve into the layers of the scalp in more detail:

Skin– It is the outermost layer of the scalp. And it is similar to the skin found throughout the body. It contains hair follicles, sebaceous glands (oil glands), and sweat glands. The scalp’s skin protects the underlying structures from environmental factors. Some factors include → regulating body temperature through sweating and providing a medium for sensory perception.
Dense Connective Tissue– Beneath the skin lies the dense connective tissue layer. This layer is rich in collagen and elastic fibres, making it strong, resilient, and resistant to stretching. It plays a vital role in protecting the skull from external forces and provides stability to the scalp.
Epicranial Aponeurosis (or Galea aponeurotica)– It is a broad, tendon-like layer of fibrous tissue that lies beneath the dense connective tissue. It plays a crucial role in connecting various muscles of the scalp, such as the frontalis and occipitalis muscles. This layer allows coordinated movements of the scalp, such as raising the eyebrows and wrinkling the forehead.
Loose Areolar Connective Tissue– Beneath the epicranial aponeurosis, there is a layer of loose areolar connective tissue. This layer acts as a cushioning and transitional layer, facilitating movement between different structures of the scalp. This tissue also contains blood vessels and nerves that supply the scalp with → oxygen, nutrients, and sensory innervation.
Periosteum– The innermost layer of the scalp is the periosteum. It is directly attached to the outer surface of the skull. The periosteum is a thin but tough membrane that covers and nourishes the bones of the skull. It plays a critical role in the healing process of any scalp injuries. It can also stimulate bone repair and regeneration.

In the upcoming section, we will find out the arterial supply in the Scalp. It includes → the Ophthalmic artery and external carotid artery.

Arterial Supply in the Scalp

The scalp is highly vascularized to support the underlying tissues. The arterial blood supply is divided into branches of the external carotid and ophthalmic arteries. Let’s explore each of these arteries and their branches in detail:

External Carotid Artery

The external carotid artery is one of the two main branches of the common carotid artery. It is located in the neck. It supplies blood to various structures in the head and neck, including the scalp. In the scalp, the external carotid artery gives rise to several branches:

Superficial Temporal Artery– The superficial temporal artery is a major branch of the external carotid artery. It is responsible for supplying blood to a significant portion of the scalp. It runs horizontally above the ear and towards the temporal region of the scalp. Along its course, it gives off numerous smaller branches that spread out over the scalp. It also provides oxygen and nutrients to the tissues.
Posterior Auricular Artery- The posterior auricular artery is another branch of the external carotid artery. It is responsible for supplying the posterior and superior parts of the ear. Although it doesn’t directly contribute to the bulk of the scalp’s blood supply. But, it does participate in the vascular network of the scalp’s surrounding regions.
Occipital Artery– This artery arises from the posterior part of the external carotid artery. It travels upward and backwards to supply the posterior scalp and the back of the head. It gives off smaller arteries that help form an extensive vascular network in the scalp.

Ophthalmic Artery

This artery is a branch of the internal carotid artery. It is another main branch of the common carotid artery. While it mainly supplies blood to the orbit (eye socket). Then, it also contributes to the blood supply of the scalp through two branches:

Supraorbital Arteries– They are branches of the ophthalmic artery. They emerge from the supraorbital notch (depression located below the eye socket) above the eye. These arteries provide blood to the upper part of the scalp and the forehead region.
Supratrochlear Arteries– The supratrochlear arteries are also branches of the ophthalmic artery. They arise close to the medial part of the supraorbital notch. And they superiorly supply blood to the central part of the forehead and the scalp area.

In the next section, we will talk about venous drainage in the scalp, which includes Superficial drainage and Deep Drainage.

Venous Drainage in the Scalp

The scalp is a highly vascularized region of the head. Blood circulation plays a crucial role in maintaining the health of the scalp and underlying structures. The venous drainage of the scalp can be categorized into two main systems:

Superficial Drainage

The superficial venous drainage of the scalp primarily involves veins that are located closer to the skin’s surface. These veins are responsible for draining blood from the superficial tissues of the scalp. There are three main groups of superficial veins:

Supratrochlear Vein– The Supratrochlear Vein is a small blood vessel that originates within the frontal region of the scalp. Positioned just above the inner portion of the eyebrow’s superciliary arch (brow ridge or bony prominence). It facilitates the drainage of blood from the uppermost area of the forehead. This vascular structure ultimately converges with the angular vein.
Supraorbital Vein– This vein originates from the forehead’s lateral region, above the eye’s orbit (socket). Like the supratrochlear vein, it also participates in draining blood from the frontal scalp. The supraorbital vein joins with the angular vein as well.
Cephalic Vein– This vein is not exclusive to the scalp. It also plays a role in the superficial venous drainage of the scalp. It is a larger vein that runs along the lateral aspect of the upper limb. It receives drainage from the lateral parts of the scalp. Eventually merges with the axillary vein in the arm.

Deep Drainage

This drainage of the scalp involves the scalp’s tissues, running alongside the arteries and nerves. The primary deep veins of the scalp include:

Superior Sagittal Sinus– This is not a vein in the conventional sense but a dural venous sinus (system of large veins). It is a large channel located within the midline of the brain. Mainly in the superior margin of the falx cerebri (a fold of the dura mater). It collects blood from various veins on the scalp’s superior aspects. And eventually drains into the confluence of sinuses.
Diploic Veins– These veins are found within the diploic layer of the skull. They are a spongy layer sandwiched between the inner and outer layers of compact bone. These veins run alongside the cranial bones and play a role in the venous drainage of the scalp.
Emissary Veins– They are small veins that connect the extracranial venous system (outside the skull) with the intracranial venous system (inside the skull). These veins pass through various foramina (openings) in the skull. And they can provide an alternative pathway for blood drainage from the scalp to the cranial cavity.

In the next part, we will get deep into the innervation in the scalp from various regions of the body. Scalp includes → the trigeminal nerves and cervical nerves.

Innervation in the Scalp

The scalp receives its innervation from two main groups of nerves. These nerves play a crucial role in providing sensory information and motor control to the scalp. They are also responsible for various sensations and movements in this area. The following are the two main groups of nerves:

Trigeminal Nerves (fifth cranial nerve)

A major nerve responsible for providing sensation to the face and scalp. It is the largest of all the cranial nerves. It is divided into three main branches, each having a specific role in scalp innervation:

Ophthalmic Branch (V1)– The ophthalmic branch of the trigeminal nerve innervates the anterior part of the scalp. It originates from the ophthalmic division of the trigeminal nerve. While it supplies sensation to → the forehead, frontal region, and the anterior part of the scalp.
Maxillary Branch (V2)– The maxillary branch of the trigeminal nerve is responsible for innervating the middle part of the scalp. This branch emerges from the maxillary division of the trigeminal nerve. It provides sensory information to the temporal region and the middle portion of the scalp.
Mandibular Branch (V3)- The mandibular branch of the trigeminal nerve supplies the posterior part of the scalp. It arises from the mandibular division of the trigeminal nerve. It provides sensation to the posterior part (occipital region) of the scalp.

Cervical Nerves

They are part of the spinal nerves originating from the cervical vertebrae (seven vertebrae) in the neck. These nerves interact with the trigeminal nerves to provide sensory and motor functions to certain areas. The specific cervical nerves involved in scalp innervation include:

Greater Occipital Nerve (C2)– The greater occipital nerve is a branch of the second cervical nerve (C2). It plays a significant role in providing sensory innervation to the posterior part of the scalp. And it includes the occipital region and the area just above the back of the neck.
Lesser Occipital Nerve (C2-C3)– This nerve is formed from the ventral rami (branches of the spinal nerve) of C2 and C3. It innervates the posterior and lateral aspects of the scalp, particularly the region behind the ears.
Third Occipital Nerve (C3)– The third occipital nerve arises from the third cervical nerve (C3). It provides sensory innervation to the posterior scalp, overlapping with the greater occipital nerve’s territory.
Greater Auricular Nerve (C2-C3)– This nerve originates from the ventral rami of C2 and C3. It supplies sensory information to the skin around the ears, including the region just above and behind the ear.
Auriculotemporal Nerve (V3)– The auriculotemporal nerve is a branch of the mandibular division of the trigeminal nerve (V3). While its primary function is to innervate the temporomandibular joint (joint connecting the jawbone to the skull). Lastly, it also contributes to sensory innervation of the scalp in the temporal region.

In the upcoming section, we will understand the various scalp conditions, which humans deal with in everyday life.

Common Scalp Conditions

The scalp develops various conditions that lead to discomfort and inconvenience. Four common scalp conditions include → dandruff, scalp psoriasis, scalp eczema, and scalp folliculitis. We will explore each of these conditions in detail:

Dandruff-in-woman's-hair Scalp conditions — Dandruff

Dandruff: Dandruff is a prevalent scalp condition characterized by flaky skin that sheds from the scalp. It’s often caused by an overgrowth of a yeast called Malassezia. Common symptoms include white or yellowish flakes on the scalp and hair, along with itching. Mild cases can be treated with dandruff shampoos containing ingredients like → pyrithione zinc, ketoconazole, or selenium sulfide. Regular use of these shampoos can help control the condition.
Scalp Psoriasis: Scalp psoriasis is an autoimmune condition. Under this condition, skin cells on the scalp grow too quickly, resulting in red, scaly patches. It can cause itchiness, burning sensations, and even hair loss in severe cases. Treatment options include medicated shampoos with → coal tar, salicylic acid, or prescription-strength corticosteroids. In some cases, phototherapy or systemic medications might be recommended to manage symptoms.
Scalp Eczema (or seborrheic dermatitis): Scalp eczema leads to red, itchy, and flaky patches on the scalp. It often occurs alongside dandruff and can be triggered by factors such as → stress, weather changes, or fungal overgrowth. Using gentle shampoos, avoiding harsh chemicals, and applying antifungal creams can provide relief.
Scalp Folliculitis: Scalp folliculitis involves the inflammation of hair follicles, often due to bacterial or fungal infections. It appears as small, pus-filled bumps and can cause itching and soreness. Keeping the scalp clean and avoiding oily hair products. While in some cases using topical antibiotics or antifungal treatments can help clear the condition.

In the next section, we will talk about Hair loss in the Scalp, types of hair loss, and how it affects the male and female.

Types of Hair Loss Affecting the Scalp

Hair loss (or alopecia) can manifest in various forms and impact individuals of all genders and ages. When it specifically affects the scalp, it can be caused by several factors. The following are the main forms of hair loss seen in human civilization:

Androgenetic Alopecia (or Male Pattern Baldness): The most prevalent form of hair loss in men. It is a hereditary condition influenced by both genetics and hormonal factors. The onset of hair loss typically commences with a retreat of the hairline. Then, it is succeeded by a gradual thinning at the crown of the head. Ultimately, this progression continues in the formation of a horseshoe-shaped pattern of remaining hair. This pattern encircles the lateral and posterior sections of the head. Dihydrotestosterone (DHT), a hormone, primarily triggers this type of hair loss. It gradually diminishes the size of hair follicles over an extended period.
Female Pattern Baldness: Female pattern hair loss, similar to male pattern baldness, is also influenced by genetic and hormonal factors. Women with this condition typically experience diffuse hair thinning over the top of the scalp. While men’s faces pronounced receding hairline. Hormones such as androgens and hormonal changes like menopause can contribute to this form of hair loss in women.
Alopecia Areata: An autoimmune disorder that causes the body’s immune system to attack hair follicles. It results in patchy hair loss on the scalp or other areas of the body. This condition can occur at any age and may lead to complete baldness in severe cases. The exact cause of alopecia areata is still not fully understood. But it is believed to have both genetic and environmental triggers.
Telogen Effluvium: Telogen effluvium is a temporary hair loss condition. It occurs due to significant stress, illness, hormonal changes, childbirth, surgery, or nutritional deficiencies. It leads to a higher number of hair follicles entering the resting (telogen) phase of the hair growth cycle. This leads to increased shedding of hair. Once the underlying trigger is resolved, most individuals experience regrowth of their hair.

Female-pattern-baldness — Female loosing hair

In the upcoming part, we will look into scalp injuries and disorders, which include scalp burns, scalp cysts, and tumors.

Scalp Injuries and Disorders

The scalp is susceptible to various injuries and disorders that can cause discomfort and require timely attention. We will explore three key aspects related to scalp health:

Scalp Injuries

Scalp injuries can occur due to → accidents, falls, or blunt trauma to the head. They can range from mild to severe and may involve different layers of the scalp. Common types of scalp injuries include:

Scalp Abrasions- Scalp abrasions are superficial injuries that result in the removal of the topmost layer of the skin. They often occur due to minor scrapes or scratches. And they can be managed with proper wound care and cleansing.
Scalp Lacerations- Lacerations are deeper cuts or tears in the scalp. They may result in bleeding and potential damage to blood vessels and nerves. Urgently clean the wound, control bleeding, and close the laceration with stitches, needing immediate medical attention.
Scalp Contusions (or bruises)- Contusions are caused by blunt force trauma to the scalp. They cause the blood vessels under the skin to break and resulting in discoloration. Most scalp contusions are not serious and resolve on their own. But severe cases may require medical evaluation.

Scalp Burns

Scalp burns are caused by exposure to hot objects, flames, chemicals, or extreme heat sources. They can vary in severity, like → first-degree, second-degree, or third-degree burns. Symptoms of scalp burns include → redness, blistering, pain, and in severe cases, charring of the skin. Treatment for scalp burns involves:

First-Aid Measures– For minor burns, we can take immediate first-aid steps. They include cooling the affected area with cold water and applying a sterile, non-stick dressing.
Medical Evaluation– Moderate to severe burns necessitate professional medical assessment. Doctors may prescribe pain relief, prescribe topical treatments, or recommend specific dressings to facilitate healing.
Burn Care and Healing– Adequate wound care is crucial to prevent infections and promote healing. The person must keep the scalp clean and use prescribed ointments. Must avoid picking at the burn site is essential during recovery.

Scalp Cysts and Tumors

Scalp cysts and tumors are growths that can develop beneath the scalp’s surface. They are usually benign (non-cancerous) or malignant (cancerous). Some common cysts and tumors:

Epidermal Cysts– Epidermal cysts are benign sac-like growths that contain keratin, a protein found in hair and skin. They are usually painless, slow-growing, and may require surgical removal if they cause discomfort or become infected.
Pilar Cysts– Benign growths are called pilar cysts that develop from hair follicles and fill with keratin. They usually have a smooth and mobile texture. Doctors might remove them for cosmetic reasons or if they cause symptoms.
Scalp Tumors– Malignant tumors can develop in the scalp, originating from the skin or underlying structures. Early detection and timely treatment are crucial for the best possible outcome.

As of now, we have almost reached the end of the article. So, let’s recap everything we have learned till now about the scalp.

Conclusion

In conclusion, the scalp is a vital part of the integumentary system. It serves as a protective covering for the head and supporting hair growth. Its health is crucial for maintaining the overall well-being and appearance of an individual. The layers include the skin, dense connective tissue, epicranial aponeurosis, loose areolar connective tissue, and periosteum. Each plays a specific role in its function and structure.

The various aspects of the scalp include → anatomy, blood supply, innervation, common conditions, and hair loss types. These aspects help individuals take better care of their scalp health. It leads to improved overall well-being and self-confidence. Regular scalp hygiene, a healthy lifestyle, and timely medical intervention can contribute to maintaining a healthy and well-functioning scalp.

Scalp: Anatomy, Functions and Disorders

Published by Editor Team on August 26, 2023August 26, 2023

Introduction to Scalp

Importance of Scalp Health

Layers of the Scalp