(trænzˈɪsθmɪən) adj1. (Anatomy) anatomy across an isthmus (a narrow strip of body tissue)2. (Physical Geography) geography across an isthmus (a narrow strip of land)
transisthmian
trans·isth·mi·an
(trans-is'mē-ăn), Across any isthmus; specifically, across the isthmus of the fornicate gyrus, denoting the gyrus transitivus.