Because of the position of the nails and the length, I did some research on the internet. Here is the result:
Arms and legs were tied or nailed to stakes and crossbars. With that the real crucifixion began. The nailing was done in such a way that the blood loss was kept to a minimum. According to anatomical tests, the nails did not have to be driven through the palms of the hands, but through the carpal bones or the space between the ulna and the radius, and through the tarsal or heel bone in order to support the body weight. The arms were possibly not attached with the palms facing forward (supination), but with the palms facing the crossbar (pronation) in order to achieve better fixation and less freedom of movement of the arms. [12] For the feet, this is confirmed by a skeleton find in Jerusalem from the 1st century, in which the nail was still stuck in the heel bone. This is also the first physical evidence of a Roman crucifixion. [13]
If the heels were nailed to the side, a cross piece called a sedile (seat) was sometimes added halfway up, on which the crucified could temporarily support his buttocks. This also relieved the crucified Christ's arms, which were attached to the crossbeam, in order to facilitate his breathing. Often the legs of the convicted person were also placed on a small crossbar (suppedaneum) so that he was not immediately pulled down by his own weight and passed out or lost too much blood with nailed limbs. Where this was customary, it was considered a favor to break the crucified Christ's feet or lower legs after a while in order to prevent him from supporting and thus shorten his agony. In addition, relatives sometimes bribed the executioners.
In 1968, archaeologists discovered the remains of a Jehohanan who had been crucified in the 1st century in Giv'at ha-Mivtar in northeast Jerusalem. The remains contained a heel bone through which a nail was driven from the side. The tip of the nail was bent, possibly because a knot was struck in the upright beam that prevented it from being pulled out of the foot. An initial inaccurate representation of the length of the nail led some to believe it had been driven through both heels, suggesting the man had been placed in some sort of side saddle position, but the true length of the nail was 11.5 cm (4.53 in.) Inch)) instead suggests that in this case of the crucifixion, the heels were nailed to opposite sides of the post. The skeleton from Giv'at ha-Mivtar is currently the only found example of an ancient crucifixion in archaeological records. Crucifixion -
https://de.qaz.wiki/wiki/Crucifixion