Measurements of posterior cranial fossa (PCF) area and linear dimensions relative to hindbrain area based on T1 weighted MRI, compared to published data from cough headache patients with apparently normal MRI (CH) and asymptomatic controls. Chen et al.  found that the PCF area in the cough headache patients was significantly smaller than controls while hindbrain areas did not differ. Thus the hindbrain/PCF ratio was significantly greater in the cough headache patients (0.78 ± 0.04 v 0.73 ± 0.06, p<005). In patient 14, the ratio was 0.82, well within the ‘posterior fossa crowdedness’ criterion.