Inserting NavBar

((Sorry for my poor English))

I created a navigation bar in html, and their styles in css. To interconect some sub-sites.
Expample video.domain.com news.domain.com, etc.
Is there any way to insert the NavBar in the header, without placing the entire HTML code?, Is there a plugin or simple code?

I have the html.. u know.. :Example:

<ul id="list-nav">
<li><a href="#">Home</a></li>
<li><a href="#">News Site</a></li>
<li><a href="#">Forum</a></li>
</ul>

Well,my code is bigger .. much bigger.
What way I can call?
I can use a short code or similar?