Do you not know that chaste women stay fresh much more than those who are not chaste? How much more in the case of the Virgin, who had never experienced the least lascivious desire that might change her body? 
The marks of the Crucifixion are limited to very small nail marks and an indication of the wound in Jesus’ side.
In a lesser known Michelangelo pietà, The Deposition, it is not the Virgin Mary who is holding Jesus’ body, but rather Nicodemus (or possibly Joseph of Arimathea), Mary Magdalene, and the Virgin Mary. There is some indication that the man in the hood is based on a self-portrait of the artist.  The sculpture is housed in the Museo dell’Opera del Duomo in Florence and is also known as the Florentine Pietà.
The pietà developed in Germany (where it is called the “Vesperbild”) about 1300, reached Italy about 1400, and was especially popular in Central European Andachtsbilder.  Many German and Polish 15th-century examples in wood greatly emphasise Christ’s wounds. The Deposition of Christ and the Lamentation or Pietà form the 13th of the Stations of the Cross, as well as one of the Seven Sorrows of the Virgin.
Paul V approved the building of the new aisle in 1609 and the Pietа was moved again, awaiting to be set in the new Choir. It was temporarily located in the room prepared to officiate the canons – the left side transept, over the altar of Sts Simon and Jude (at present the altar of St Joseph). After the decision to adorn the altar of the Chapel of the Choir with a mosaic representing the Immaculate Conception, it was noted that the presence of two Madonnas was not possible.
Italy’s renowned sculptor Giacome Manzu declared that he was the only one able to restore the statue.
An examination of each figure reveals that their proportions are not entirely natural in relation to the other. Although their heads are proportional, the Virgin’s body is larger than Christ’s body. She appears so large that if she stood up, she would likely tower over her son. The reason Michelangelo did this was probably because it was necessary so that the Virgin could support her son on her lap; had her body been smaller, it might have been very difficult or awkward for her to have held an adult male as gracefully as she does. To assist in this matter, Michelangelo has amassed the garments on her lap into a sea of folded drapery to make her look larger. While this drapery serves this practical purpose, it also allowed Michelangelo to display his virtuosity and superb technique when using a drill to cut deeply into the marble. After his work on the marble was complete, the marble looked less like stone and more like actual cloth because of its multiplicity of natural-looking folds, curves, and deep recesses.
The scene of the Pieta shows the Virgin Mary holding the dead body of Christ after his crucifixion, death, and removal from the cross, but before he was placed in the tomb. This is one of the key events from the life of the Virgin, known as the Seven Sorrows of Mary, which were the subject of Catholic devotional prayers. The subject matter was one which would have probably been known by many people, but in the late fifteenth century it was depicted in artworks more commonly in France and Germany than in Italy.
The format of the Virgin bearing the body of Christ on her knees was standard until the 16th century, when, influenced by the Renaissance concern with logic and proportions, artists usually depicted Christ lying at the Virgin’s feet, with only his head propped against her knees. This form was adopted by Italian Baroque art and was passed on to Spain, Flanders, and Holland.
The theme, which has no literary source but grew out of the theme of the lamentation over Christ’s body, first appeared in the early 14th century in Germany. It soon spread to France and enjoyed great popularity in northern Europe in the 14th and 15th centuries. Although the Pietà remained mostly a Franco-German theme, its supreme representation is that completed by Michelangelo in 1499 and housed in St. Peter’s Basilica in Rome. Influenced by the northern style, Michelangelo draped the figure of Christ across Mary’s lap. Through this pyramidal design and the details of his figures, Michelangelo created a scene that displayed at once agony, solemnity, and heroic resignation.