The hand gesture shown is called Hridaya Mudra, Heart gesture, and helps to revitalize energy from and to the heart, then nourishing other areas of self.
How I practice this mudra: Before and after several rounds of sun salutations, sitting comfortably, engaging with the breath. I especially enjoy feeling the energetic pulses through my hands and into the minor Hridaya chakra below the heart center.
Why I practice this mudra: I feel my heart needs a lot of healing right now. The APMB text states, "the middle and ring fingers relate directly to nadis (energy centers) connected to the heart, while the thumb closes the pranic circuit and acts as an energizer, diverting the flow of prana from the hands to the nadis." Truth! I feel an actual conservation and continuation of energy in my body through my arms and hands holding this mudra especially after practicing a heat generating flow. The text also states, "helps to release pent-up emotion and unburden the heart. It may be practiced during emotional conflict and crisis." I mean, isn't that just everything we need right now, right there?
If you explore this mudra, I'd love to hear your revelations!