Much less common than spinal<unk> (1:9)
Usually caused by local spread of infection or inoculation during surgery or trauma
Usually isolated to calvarium due to adherence of dura to foramen magnum
Epidural abscess 
Intracranial hemorrhage
Subdural empyema
Intra-axial
Discitis
Hemorrhagic stroke 
Vertebral osteomyelitis
Traumatic intracerebral hemorrhage