Word provides a handy shortcut that allows you to quickly jump to either the top or bottom of a column in a table. This can be quite helpful, particularly if you are working with very long tables. If you press Alt+PgUp, you are taken to the first cell in the column, where the insertion point is placed just before the first character in the cell.
Likewise, you can jump to the last cell in a column by pressing Alt+PgDn. This moves the insertion point to the last cell in the column, where it is positioned just before the first character in the cell.
If you try to use these shortcuts outside of a table, they have no effect.