Wordpress Issue: Site Name With The Title Of Every New Page Only In Search Results

I have my website made on Wordpress CMS. It has worked brilliantly for me and has provided me results that I wanted but sometimes, I get an issue that I don't understand. I try to solve it my self, but when I can't I come to forums like this to seek some help.

The issue I am currently having is that every page of my website that is newly indexed by the search engines shows the name of the site with it. The actual problem is that I have edited the header.php file in such a way that it should not display the name of the website with page's title. In a browser, it obeys my commands but when search engines indexes my pages, they show the name of the website with the title of the page.

Let me provide some more details. The name of my website is Human Anatomy. One of the pages of my website titles "Esophagus". When you go directly to the page by clicking the link, you will see that the title is fine. There is no "Human Anatomy" with it. But when you go to google and type "Esophagus Human Anatomy" and go to the second page of search results, you fill find the same page (Esophagus) under the title "Esophagus - Human Anatomy" in google results.

The problem is common to almost all pages of the website. Any newly created page, when indexed by google displays similar title, while according to my settings it shouldn't do it.

The problem is made even more complex by the fact that when you type title of the page followed by "mananatomy.com" in the google search, the resutls displayed no more contain the term "human anatomy" with the title of the pages. For example you go to google.com and type "Esophagus mananatomy.com", you will see that the title of the page doesn't contain the term "Human anatomy". This makes me think about the nature of the problem that it might be google's own problem and nothing is wrong with my website but yet I have to agree that google responds to actions on my website. it doesn't do anything related to my website on its own.

So you see the problem is a bit complex and I don't understand what to do with it. When I researched on the internet about the possible causes of the problem, I found some glimpses that the sitemap might be causing it. I am currently using "Google XML Sitemaps" plugin for wordpress. I have checked all its settings and everything looks ok. As a precautionary measure, i have also checked the code of the sitemap.xml file. It displays the following lines

<url>		<loc>http://www.mananatomy.com/digestive-system/esophagus;		<lastmod>2011-01-26T19:48:51+00:00</lastmod>		<changefreq>daily</changefreq>		<priority>1.0</priority>	</url>

I couldn't find any title thing in the sitempa.xml file so I figure it might not be the cause of the problem.

So my conclusions are that both google and sitemap are not causing the issue. Wordpress by default ads the name of the website with the titles of all newly created pages. I have modified it but I think I haven't done it correctly so that the google bot is still seeing the default title of the page, while the browsers read the ones I like them to read.

Anyone with any kind of help is welcome. I really want to solve this issue and make the search engines index the correct title of my website. The addition of the term "Human Anatomy" with the title of pages of my website is causing them appear lower in SERPs because of dilution. The words I want them to rank for are not the only words contained in the title and this is causing an adverse effect. If someone can provide me some advice on this, I would really appreciate.