The "danger area of the scalp" refers to a specific layer of tissue that poses a risk for infection spread.
Understanding the Danger Area
The scalp is composed of several layers, and one layer, in particular, is known as the "danger area" due to its anatomical features.
The Layer of Concern
- Loose Areolar Connective Tissue: This is the layer specifically identified as the danger area [18]. It's found beneath the scalp's skin and above the periosteum (the membrane covering the skull bones).
Why It's Dangerous
The reason this layer is considered dangerous lies in the presence of:
-
Valveless Emissary Veins: These are veins that pass through the skull bones, connecting the superficial scalp veins in the subaponeurotic space with the intracranial venous sinuses within the skull [18]. These veins are unique because, unlike most veins, they lack valves.
- Absence of Valves: The absence of valves means that blood (and any infection it may carry) can flow in either direction between the scalp veins and the intracranial venous sinuses, without valves preventing backward flow.
Risk of Infection
- Pathway for Infection: This connection between the scalp and the intracranial sinuses means that an infection in the scalp can potentially spread through these emissary veins and reach the meninges (the membranes surrounding the brain and spinal cord) [18].
- Meningitis or Intracranial Abscess: If an infection reaches the meninges, it can cause meningitis, a serious inflammation of these protective membranes. The infection could also cause an intracranial abscess (a collection of pus within the brain).
Practical Implications
- Scalp Injuries: Small scalp injuries or infections, especially in the "danger area", must be carefully monitored.
- Prompt Medical Attention: Any signs of infection or inflammation in the scalp should be evaluated by a medical professional, especially if there are other symptoms like fever, headache, or confusion.
- Treatment: Treatment may involve antibiotics or drainage of the infection.
Summary
The danger area of the scalp is the layer of loose areolar connective tissue containing valveless emissary veins, creating a pathway for infections to spread from the scalp to the intracranial venous sinuses and potentially to the meninges.
