It’s a bit like why drilling into a wall might make the lights go out if you hit a cable. Your brain only registers “feeling” in any part of your body because a nerve carried that information to it. The nerves from your lower arm and hand pass your elbow. Hitting the nerve directly causes signals in it which you brain interprets as pain in your fingers. Presumably the nerves for the pinky side of your hand are slightly more exposed.
It’s a bit like why drilling into a wall might make the lights go out if you hit a cable. Your brain only registers “feeling” in any part of your body because a nerve carried that information to it. The nerves from your lower arm and hand pass your elbow. Hitting the nerve directly causes signals in it which you brain interprets as pain in your fingers. Presumably the nerves for the pinky side of your hand are slightly more exposed.