Q. Modern researchers insist that Jesus was nailed through the wrists, so why do the stigmata always appear in the palms?
A. The stigmata are wounds or scars corresponding in some way to those in the feet, wrists or hands, side, and brow of the crucified Christ. They are mysteriously imprinted in the flesh of a human being (including several canonized saints) and may be painful. They may be recurrent or permanent, visible to all or visible only to the stigmatist (the one who bears them).
Not all occurrences of the stigmata have appeared in the palms. St. Francis of Assisi (d. 1226), the first person we know for sure who received them, had his wrists and feet pierced by nails. Meanwhile, the actual location of the piercings that Jesus endured is still hotly debated. Various scholars have made the case that the nails could have pierced the hands or the wrists (the same New Testament Greek word can refer to both), or even that they entered the hand at an angle and exited the wrist. The precise position is not a matter of faith.
Genuine stigmata appear to result from a believer’s deep faith and intense desire to share Christ’s sufferings. Since it’s a miraculous gift received through meditation on His wounds, we shouldn’t be surprised that the wounds might appear where the victim expects them to be, not necessarily where His wounds actually were. Centuries of sacred art have depicted Jesus’ wounds in His palms, so when the stigmata appear there, the stigmatist is made to understand that he or she is being asked to bear this suffering in union with Christ on the Cross.
In short: The stigmata’s purpose is not to present us an exact medical model of Jesus’ wounds. Otherwise, all genuine occurrences of them would look exactly alike — yet they do not. Instead, through this extraordinary phenomenon, those who witness it are called to grow deeper in union with our crucified Lord.