Middle ear to sounds of higher frequency, because these are better taken up by the inner ear (which also responds to higher frequencies than those of non-mammals). The malleus, or "hammer", evolved from the articular bone of the lower jaw, and the incus, or "anvil", from the quadrate. In other vertebrates, these bones form the primary jaw joint, but the expansion of the dentary bone in mammals led to the evolution of an entirely new jaw joint, freeing up the old joint to become part of the ear. For a period of time, both jaw joints existed together, one medially and one
Anvil forging tool. Common methods of attaching an anvil are spikes, chains, steel or iron straps, clips, bolts where there are holes provided, and cables. A smith would use whatever was at hand, as long as it held the anvil firmly in place. The anvil is placed as near to the forge as is convenient, generally no more than one step from the forge to prevent heat loss in the work piece. The most common base traditionally was a hard wood log or large timber buried several feet into the floor of the forge shop floor. This was done to make