MBRTouches(g1,g2)

Returns 1 or 0 to indicate whether the Minimum Bounding Rectangles of
the two geometries g1 and g2 touch. Two geometries spatially touch if
the interiors of the geometries do not intersect, but the boundary of
one of the geometries intersects either the boundary or the interior of
the other.

URL: http://dev.mysql.com/doc/refman/5.1/en/relations-on-geometry-mbr.html

