What are the normal measurements of thyroid gland?

Everyone differs. There are standard ranges of normal, but many, many patients feel better when they're treated not by the numbers, but by their symptoms. Google "stop the thyroid madness" for more info. Weird name, helpful site.
See the diagram. The size of virtually all organs in the body varies by age, gender, and some even by ethnicity. The data is readily available and I have enclosed a simple diagram/picture here for your learning/curiosity. Have fun learning. Good luck.