The authors describe the clinical, radiological, and postmortem findin
gs of a case of cloverleaf skull syndrome. The presence of hindbrain h
erniation, abnormal cervical segmentation, and atlantoaxial subluxatio
n illustrate the anatomical complexity of the skull base and the crani
ocervical junction that may coexist in this condition. Unavoidable div
ision of occipital emissary veins during elevation of the skin flap at
the time of vault remodeling surgery led to an acute and, ultimately,
fatal rise in intracranial pressure. Postmortem examination and revie
w of magnetic resonance imaging revealed an anomalous pattern of venou
s drainage of the intracranial structures that appeared to have develo
ped in response to venous obstruction, secondary to intraosseous venou
s sinuses and stenosis of the jugular foramina. The relationship betwe
en venous hypertension, hindbrain herniation, and hydrocephalus in thi
s situation is reviewed, and the implications for evaluation and manag
ement of this vexing disorder are discussed.