Histomorphological study on hypocellularity in mastoid processes from archaeological human skeletons.

Objective: To evaluate processes causing two types of mastoid hypocellularity (Type 1 and Type 3), and to provide histomorphological criteria for a differential diagnosis in archaeological human bone.

Materials And Methods: Eight human crania from the early medieval cemetery in Dirmstein (Rhineland-Palatinate, Germany) displaying secondary obliteration of mastoid air cells were analyzed using light-microscopy and backscattered electron imaging.

Results: In Type 1 hypocellularity, obliteration starts in the non-pneumatized portion of the mastoid process and extends into the pneumatized portion. The findings could represent a chronic, maybe recurrent condition related to a pathologically altered middle ear mucosa in early childhood. In Type 3, a sequence of resorptive and proliferative processes are present and are consistent with a healing stage of mastoiditis.

Conclusions: Using histomorphology, in vivo processes resulting in different types of mastoid hypocellularity can be assessed, even in bones that have undergone some degree of diagenesis.

Significance: The study provides methods to evaluate the etiology of histomorphological changes of the mastoid process, which potentially provides insight into the presence of infection and inflammation in past populations.

Limitations: Diagenetic modifications of archaeological bone can hinder assessment of histomorphological change, requiring careful evaluation during analysis.

Suggestions For Further Research: Including histomorphology in future studies on archaeological human crania can contribute to an improved differential diagnosis of pathological conditions in the middle ear region.