The median eminence is generally defined as the portion of the ventral hypothalamus from which the portal vessels arise.

[1] The median eminence is a small swelling on the tuber cinereum, posterior to and on top of the pituitary stalk; it lies in the area roughly bounded on its posterolateral region by the cerebral peduncles, and on its anterolateral region by the optic chiasm.

As one of the seven areas of the brain devoid of a blood–brain barrier,[2] the median eminence is a circumventricular organ having permeable capillaries.

The pars nervosa (part of the posterior pituitary gland) is continuous with the median eminence via the infundibular stalk.

[7] Further, anatomical evidence exists for bidirectional communication between the median eminence and the arcuate and ventromedial nucleus of the hypothalamus.