Hypothalamic and pituitary injury.

The hypothalamic-pituitary axis is recognized to an increasing extent as a physiological unit which influences and is influenced by endocrine and autonomic function. Anatomically, however, a clear distinction is to be drawn, with regard to both cellular and vascular anatomy, betweenthe neural (hypothalamus and neurohypophysis) and the glandular epithelial (pars distalis) components of the axis. The anatomical situation of lesions which may cause physiological disturbances of the hypothalamic-pituitary axis has to be considered, as it appears in some cases at least that a precise location may be required to disrupt the physiological integrity of the axis. Despite present-day refinements of biochemical diagnosis, the final word regarding the correlation of clinical findings with anatomical lesions still rests with the histopathologist. In the present paper the infundibulum is considered with the hypothalamus and the pituitary stalk and neurohypophysis with the pituitary gland, for although these structures form an anatomical continuum the interposition of the diaphragma sellae between the infundibulum and neurohypophysis results in the development of different lesions in these two areas after head injury. The effects of trauma on the hypothalamicpituitary axis have been observed and recorded for nearly a century, one of the oldest observations being that of Kahler (1886), who reported polyuria following a basal fracture which ran through the pituitary fossa. Most of the reports, however, have been clinical, without pathological correlation. The few published pathological reports have been concerned mainly with the changes in the pituitary gland in long survivors (for references see Daniel and Treip, 1961 and 1966a). Even fewer descriptions of post-traumatic hypothalamic changes are available (Vonderahe, 1940; Henzi, 1952; Goldman and Jacobs, 1960; Orthner and Meyer, 1967). Hypothalamic Lesions