Fig. 2

Potential pathophysiological links with the pituitary gland in cluster headache. (+) arguments pro (-) arguments con. “Size is not everything” is a reference to an article of Levy et al. [16]. V1 is the ophthalmic branch of the trigeminal nerve. HPA = hypothalamic-pituitary axis. The figure is further explained in the text under the heading “pathophysiology”