Answer
Serrate sutures appear as wavy lines along which the adjoining bones firmly interlock with each other by their serrated margins, like pieces of a jigsaw puzzle. Lap (squamous) sutures occur where two bones have overlapping beveled edges, like a miter joint in carpentry. Plane (butt) sutures occur where two bones have straight nonoverlapping edges. The two bones merely border on each other, like two boards glued together in a butt joint.
Work Step by Step
Sutures page 276