Final answer:
Nail discoloration can indicate a serious problem with the nail bed, a specialized structure rich in blood vessels that lies under the nail plate, and can be a sign of issues with oxygen saturation or blood flow.
Step-by-step explanation:
Discoloration of the nail can indicate a serious problem in the nail bed. The nail bed is the area of skin underneath the nail plate that is rich in blood vessels, giving it a pink color. It is a specialized structure of the epidermis found at the tips of our fingers and toes. Discoloration here can suggest issues with oxygen saturation or blood flow; for instance, a bluish or purple hue could indicate low oxygen saturation. This is an important consideration for healthcare professionals, including EMTs, who might perform a blanch test to check for adequate blood flow. The nail plate, in contrast, is the external part of the nail and is composed of densely packed dead keratinocytes, which means discoloration in the nail plate itself typically doesn't indicate issues with blood flow or oxygenation but may signal other health problems like fungal infections.