There is no region in human anatomy called the "coastal region."

It's possible you're thinking of:

* The costal margins: This refers to the lower borders of the rib cage, formed by the costal cartilages that connect the ribs to the sternum (breastbone).

* The coastal area: This term is more common in geography, referring to a land area near the coast.

Let me know if you can provide more context or a different way to phrase your question!