When does the spheno-occipital synchondrosis close?

In forensic work, the spheno-occipital synchondrosis helps identify the deceased as a child or young adult. In the past, it was generally held that the synchondrosis closed between the late teens and 25 years, but recent studies have suggested closure in adolescence. There are also suggestions that the age at closure recorded might be influenced by ancestry and the technique used to study the joint. This comprehensive review of the literature of the past 60 years concludes that the age of closure of the spheno-occipital synchondrosis is very variable, from childhood to the mid-twenties, with no obvious association with the geographical location of the study population. We note that some studies on bony specimens indicated later closure than others using clinical images and draw attention to a possible misinterpretation of the so-called "fusion scar" which might explain this incongruity. Despite an increasing acceptance that the synchondrosis usually closes in adolescence, we are concerned that insufficient heed is being paid to reports of closure in childhood and in the early to mid-twenties. We conclude that, for forensic purposes, it is unwise to declare that the synchondrosis closes in adolescence. It would be safer to state that a closed synchondrosis indicates a person 6 years or over and that an open synchondrosis may be seen up to the mid-twenties. Clearly, for younger individuals, the dentition and, for all individuals in this age range, documentation of unfused postcranial epiphyses would be important in attempting to narrow this very broad estimation of age.