Bosch Ears With Knife By Hieronymus Sculpture

Ears With Knife By Hieronymus Bosch, sculpture taken from the Bosch painting of The garden of Early Delights. Two enormous ears, held together by an arrow and a knife jammed in between. Is there an allegorical medieval symbolism behind this, or are the horrible tortures one might expect in hell pictured here once more? Is the monogram on the knife an M of the B of Bosch? Maybe we will never know what Bosch had between his ears, when he was painting this picture.