Page Splits in SQL SERVER 2005
A page is 8Kbytes of data and an extent contains 8 pages.
When you insert rows into a table they go on a page.Pages have slots
and our rows will go in one of the slot of the page.So if our row
requires more space than what is available then SQL Server creates a
new page and moves the rows to the right or left of our modification on
to it. This technique is called a page split.