Is the "ʿajb al-dhanab" (coccyx/tailbone) actually the coccyx, even though some people are born without a coccyx, and humans are not created from it, and there is no cell or nucleus associated with it during the creation process?

The noble prophetic hadith (definition) about the greatness of the "coccyx bone" (ajb adh-dhanab), which the earth does not consume and remains to reconstruct the human being on the Day of Resurrection, is authentic and well-established. The coccyx bone is a small bone at the base of the spine, considered the head of the coccyx, and the hadith describes it as being like a mustard seed. There are different interpretations regarding its meaning; the majority view that it does not decay and the earth does not consume it, while al-Muzani disagreed, stating that it does decay. This generality is specified for some bodies, such as the bodies of prophets, which the earth does not consume. As for the absence of the coccyx (caudal regression syndrome) in some newborns, it is a rare birth defect that occurs during the embryonic stage, and this condition does not contradict the hadith; this part may exist during creation and then regress, just as a seed produces a plant, and then we may not find any trace of it.