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Erythema above the lips, making it more difficult to distinguish the vermilion border.
|Latin||pars intermedia labiorum oris|
The vermilion border is the normally sharp demarcation between the lip (red colored) and the adjacent normal skin. It represents the change in the epidermis from highly keratinized external skin to less keratinized internal skin. It has no sebaceous glands, sweat glands, or hair.
There are 2 reasons for the border being red:
1. The epithelium is thin.
2. This epithelium contains eleidin which is transparent and the blood vessels are near the surface of the papillary layer, revealing the 'red blood cell' color. At the angles of the mouth, there are sebaceous glands, without hair follicles, which are called Fordyce's spots.