system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is elbow skin drier than skin on the rest of your body?
gpt
I would guess that relative to the other parts of your body, the skin around your elbows has fewer sebaceous glands. Sebaceous glands secrete oils that cover your skin to protect it from the outside world and prevent your skin from drying out. 

When you don't have enough of these oils, whether it be from dry weather, frequently stripping them away with soaps, or other causes, the skin will dry out and might crack.