Post-mortem distortion resulting from the pressure of overlying sediments (i.e. grave backfill) is one of the taphonomic factors capable of altering the geometry of buried and subsequently recovered skeletal remains. If pressure distortion is a frequent occurrence, it could systematically flaw the outcome of an anthropological examination. To study the patterns of post-mortem distortion in buried crania and shape alterations associated with a specimen's in situ position, 46 male crania recovered from an Old Slavic graveyard (Pohansko, Czech Republic) were analysed together with control specimens from four modern European osteological collections (N = 207) using geometric morphometrics. The results indicate a common pattern of shape change in buried skulls associated with their in situ orientation. However, as the overall shape variation between the Old Slavic crania (which, with their tendency towards longer, narrower shapes differed markedly from the modern Czech crania) oriented in situ on their back and side reflects the duality of dolichocranial and brachycranial forms, it seems likely that the in situ positioning of the crania stemmed from their original morphology. The lack of substantial effect of the in situ orientation on the cranial morphology is associated with a larger cranial size and a tendency for sturdiness in the Old Slavic subsample. Both of these characteristics are likely to be contributing to the resistance of these crania to taphonomic alterations. Copyright © 2013 John Wiley & Sons, Ltd.