Updated project metadata. Diverse immune cells move from the calvaria marrow into the dura mater via recently discovered skull-meninges connections (SMCs). Yet, how the calvaria bone marrow is different from the other bones and whether it plays a special role in human diseases remain unknown. Using multi-omics approaches and whole mouse transparency we reveal that bone marrow cells are highly heterogeneous across the mouse body. The calvaria harbors the most distinct molecular signature with hundreds of differentially expressed genes and proteins. Acute brain injury induces skull-specific outcomes including increased calvaria cell numbers. Moreover, TSPO-PET imaging of stroke, dementia and multiple sclerosis patients demonstrate increased inflammation in the human skull, mirroring the underlying brain inflammation.