The Gospel of Luke says that the two thieves crucified on either side of Jesus were called 'Dismas', the good thief, who repented for his sins and 'Gestas', the unrepentant thief, who reviled and mocked Jesus.
As can be seen both thieves have been crucified in slightly different but equally painful ways with one having his arms extended up and over the back of the crossbeam while his feet are nailed through the ankles to either side of the vertical wooden beam.
The other thief is anchored to his cross in a similar manner to Jesus with iron nails driven through the palms of the hands and other nails through both feet. Again, a series of ropes have been used to hold both men on to their crosses.