FWIW, Central Am. is a part of North Am., and includes Greenland. We're speaking continents, not regions; my bold.
http://encyclopedia2.thefreedictionary.com/North+America+(continent) North America, third largest continent (1990 est. pop. 365,000,000), c.9,400,000 sq mi (24,346,000 sq km), the northern of the two continents of the Western Hemisphere. North America includes all of the mainland and related offshore islands lying N of the Isthmus of Panama (which connects it with South America).
http://www.uen.org/utahlink/activities/view_activity.cgi?activity_id=3795 United States Canada Mexico Greenland Costa Rica El Salvador Barbados Trinidad and Tobago Haiti Guatemala Belize Honduras Nicaragua Panama Cuba St. Kitts and Nevis St. Vincent and the Grenadines Jamaica Dominican Republic Antigua and Barbuda Dominica Bahamas St. Lucia Grenada