For me it was done as a part of a series of images, all focusing on imaging the injured finger and getting other stuff out of the way. The tech was very particular about how everything was oriented and twisted. Something like this.

https://xkcd.com/600/

Serious answer - I’m not a medical professional, but I’ve hurt a finger recently. This is one of the standard positions for x-raying a hand. Splays out all the fingers while leaving them supported for stability.