Your scalp is made of three layers that cover the top of your skull. Beneath your hair are layers of skin, connective tissue with blood vessels and muscle. These layers are loosely attached to your scull by a type of connective tissue called the pericranium. In addition to covering and protecting your skull, you need your scalp for growing hair and creating facial expressions.
Hair
The scalp is covered in follicles that are responsible for growing your hair. While most people have full heads of hair when they are young, there are many situations that can cause you to lose your hair. Hereditary hair loss can occur in both men and women and lead to distinct patterns called "male-pattern baldness" and "female-pattern alopecia." Whether your hair loss is caused by genetics, disease, medication or a physical accident, it can have a significant impact on your self-esteem.
Skin
The skin on your scalp is one of the thickest sections of skin on your body. It is thickest at the back of your head and gradually become thinner at the front. It has hair follicles, sweat glands and sebaceous glands that produce oil. The oil glands and hair follicles, which form close to your skin's surface, can be the source of various medical and cosmetic conditions. Skin conditions that commonly occur on the scalp include dandruff, seborrhoea and seborrheic dermatitis.
Connective Tissue
Beneath your scalp's skin is a thin layer of connective tissue called the superficial fascia. This tissue, which is tightly attached to your skin by special fibres, houses blood vessels, fat, nerves and parts of the lymphatic system. Some pieces of hair are lodged as far down as this layer, which holds blood vessels running along the sides and across the top of your head. Infections can cause the lymphatic nodes within this tissue to become swollen.
Muscle
Under your scalp's blood vessels and nerves is a muscle called the occipitofrontalis. This muscle, which covers your whole scalp, and is made of two attached segments called the occipitalis and the frontalis. These muscles contract to raise your eyebrows, wrinkle your forehead and contribute to facial expressions. When the frontalis contracts, your scalp moves forward and when your occipitalis contracts your scalp moves back. Both muscle segments are controlled by signals from branching sections of your facial nerve.
Skull
Your scalp is attached to your skull by a layer of connective tissue called the pericranium. This section of your skull, known as your cranium, is designed to protect your brain. It is made of eight bones joined together at seams that are called sutures. The coronal and lamboid sutures are major joints that run parallel across the top front and back of your skull.
References
- Chestofbooks.com: The Scalp
- International Society of Hair Restoration Surgery: About Hair Loss and Treatment
- International Society of Hair Restoration Surgery: Scalp Skin Conditions & Disorders
- Chestofbooks.com: The Arteries of the Scalp
- Human Anatomy: The Muscles of the Scalp
- A Human Face: Anatomy of the Human Skull
