27.3.7 Column-span and row-span extent
Figure 27-2 shows the range of cells that are given headers="cspan1" or headers="rspan2", or both, when ColSpanIDs=Yes, RowSpanIDs=Yes, ColSpanHead=cspan, and RowSpanHead=rspan.
Figure 27-2 Extent of column and row spans
> 27 Marking HTML table cells for WAI > 27.3 Using the id/headers method to identify table cells > 27.3.7 Column-span and row-span extent