Human Anatomy and Physiology

When does a baby's coccyx fuse together?



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Q: When does a baby's coccyx fuse together? One journal article abstract indicates that a baby's sacrum and coccyx both ossify -change from a soft tissue to a hard bony tissue-and invariably "fuse in an organized temporal pattern from the fetal period to the age of 30". Another abstract states that the coccyx begins to ossify only after birth, and that, while its three or four articulating segments usually become fused together over time, the first segment doesn't always fuse with the second. The Singapore Science Centre asserts that the coccyx has four, or even five, small vertebra that are completely fused into a single triangular bone by the age of 20 or 30. Erik Dalton, PhD, however, maintains that it is normal for the coccygeal vertebrae to remain somewhat flexible even in adults, citing a medical research paper by Postacchini & Massobrio, who found this to be true in more than 90% of their test subjects. "Postnatal maturation of the sacrum and coccyx: MR imaging, helical CT, and conventional radiography"; DR Broome, LA Hayman, RC Herrick, RM Braverman, RB Glass and LM Fahr "Coccygodynia: Evaluation and Management"; Guy R. Fogel, MD, Paul Y. Cunningham, III, MD and Stephen I. Esses, MD Singapore Science Centre: Question No. 11915 "Coccyx Controversy"; Erik Dalton, PhD