The sword in Mary's breast is a defining attribute of the Sorrowful Mother, but beyond that the statue has a number of unusual characteristics. As in Immaculate Conception images but rarely otherwise, Mary's right heel crushes the head of a snake, referencing Genesis 3:15, "I will put enmities between thee and the woman, and thy seed and her seed; she shall crush thy head, and thou shalt lie in wait for her heel."
Below the serpent's head is a skull. This is a common feature of earlier crucifixes that used a skull to as a literal reference to Golgotha, the "place of the skull" where Jesus was crucified and tradition held that Adam was buried. However, it may be that in this case the collocation of serpent and skull was intended to symbolize sin and death respectively.
The statue's crown is also unusual. It is a defining attribute of Our Lady of Guadalupe, and one finds it on rare occasions in Immaculate Conception images, but as yet I have not seen it on Our Lady of Sorrows.
The red cloth in the left hand is also remarkable. Only a few Sorrowful Mother images feature a cloth in the left hand, and in all the ones that I have seen the cloth is white.
As for the crucifix above the Dolorosa, there is
another Our Lady of Sorrows
in Munich that is placed before an image of the Crucifixion. Usually the two image types are presented separately, but in Bavaria, Austria, and Croatia it is not uncommon to see a statue of Mary placed beneath the corpus of a wayside crucifix
(example),
and this custom may have influenced presentations like this one.
The figure on the crucifix is like others of the 18th century except for the addition of a second, regal crown atop the crown of thorns and the silver pendant hanging upon the breast. The pendant's form – a "Valentine's heart" with a flame on top – is adapted from Sacred Heart images.
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Read more about Our Lady of Sorrows and about crosses and crucifixes.