In striking parallel to Michelangelo's unfinished sculptural works, there is a high degree of contrast between different parts of the sheet the body of the Child, which is so highly finished that it is impossible to even detect the artist's hand and the face and body of the Madonna, which is roughed out in the barest form of a sketch.
WSJ: Masterpieces on a Shopping List | Michelangelo Master Drawings | Museum of Fine Arts Boston | By Cammy Brothers