The posterior pituitary gland, or neurohypophysis, is a lobe of the pituitary gland that stores and releases hormones produced by the hypothalamus, primarily oxytocin and vasopressin (antidiuretic hormone). It plays a crucial role in regulating water balance, blood pressure, and reproductive functions. Disorders such as diabetes insipidus, characterised by excessive thirst and urination due to insufficient vasopressin, highlight its clinical significance.