Shortening along the Himalayan arc of continental convergence is approximately in the radial direction. If the underthrusting foot-wall block (India) is not deformed, the hanging-wall block (Tibet) needs to stretch along the arc, as suggested by radial grabens in southern Tibet. In contrast, the Nanga Parbat–Haramosh massif and the western Himalayan syntaxis are part of a 250-km-long antiform that strikes in the radial direction (northeast) and verges northwest. The Nanga Parbat antiform is the structural and topographic expression of arc-parallel shortening that compensates for arc-parallel extension in southern Tibet. This shortening is predicted to be as high as 12 mm/yr.