[calvaria, Latin = top part of skull, from calvus = bald]

1. OUTER TABLE = outer layer of cortical bone
   • well defined and of very high attenuation
   • very low signal intensity
2. DIPLOË = layer of cancellous bone
   [diploë from diploos, Latin = double]
   • slightly lower attenuation than outer table
   • low signal intensity on T1WI during first 2 decades
   • high signal intensity later ← fatty marrow conversion
3. INNER TABLE = inner layer of cortical bone
   • well defined and of very high attenuation
   • very low signal intensity
4. DURA MATER = double-layered membrane composed of
   1. outer layer = periosteum of inner table
   2. inner layer = dura mater proper
   
   The usually continuous double-layered membrane separates to form:
   • dural venous sinuses
   • tentorium cerebelli, falx cerebri, falx cerebelli
   • diaphragm sellae
   • short low-signal-intensity segments with enhancement (no blood-brain barrier) most prominent over convexities