Size and position of the human adhaesio interthalamica.

In 50 human brains, we investigated the size of the adhaesio interthalamica, length of CA-CP line, position of the centre of adhaesio interthalamica, and the distance between the corpus callosum and adhaesio interthalamica. Interthalamic adhesion was absent in 11 brains (22%) and was duplicated in 1 brain. In all 50 brains, length of the intercommissural line (CA-CP) had a mean value of 2.56 cm, in brains with the interthalamic adhesion 2.48 cm, and 2.56 cm in brains without it. t-test for this difference showed no significant result for a probability of 0.05 (t = 1.95). Midsagittal section area of adhaesio interthalamica had a mean value of 13.1 mm2 (min = 1.5 mm2; max = 34 mm2). There is no correlation between the length of CA-CP line and the size of the midsagittal section area of adhaesio interthalamica (the correlation coefficient was 0.06). The centre of adhaesio interthalamica was most often situated above the CA-CP line and around the perpendicular line through its middle portion. The distance between the corpus callosum and interthalamic adhesion, measured in standardized system of CA-CP line, had a mean value 1.4 cm (min = 0.7 cm; max = 2.3 cm). Our results confirm the opinions that the presence of size of the interthalamic adhaesion depends not directly on the size of the corresponding brain (diencephalon).