ABSTRACT
The medial surface of the thalamus is usually connected to the opposite thalamus by a flat, grey interthalamic adhesion behind the interventricular foramen; its anteroposterior dimension is on average about 1cm and it is sometimes multiple, occasionally absent, and contains neurons, some of their axons crossing the midline, though many recurving back from this (Williams et al., 1995). It may be lamellar, arciform, prismatic, and even sometimes double, especially in women (see Viller [1887] for review). Its functional aspect has always been regarded as being of minor importance. As far back as in 1887, Viller concluded his study as follows: “[c’est un] vestige ancestral qui n’a aucune signification fonctionnelle” ([it is an] ancestral remnant which has no functional meaning” (p. 57). Exactly a century later, nothing has changed: “Funktionell scheint sie bedeutungslos zu zein” (it seems to be functionally meaningless) (Töndury & Kubik, 1987).
