Sitar knowledge: Trick for long middle and index finger stretch.

I am very happy to find this picture of Ustad Vilayat Khan Sahab capturing this trick. Notice that the index and the middle finger form a 90 degree angle. It is not possible to stretch the fingers this much in a flat position sideways. For example, this technique is used to play Sa with index (fixed), Re and Ga with the middle finger moving. This is one of the important left hand techniques of sitar to learn.