In human anatomy, the ulnar nerve was a nerve that ran near the ulna bone; one of the two bones that the forearm was comprised of. The nerve was one of the largest nerves in the body that was also unprotected by muscle or bone. It was covered by the skin and thus was quite prone to injury. When cleanly struck by an impact, it would send an electric jolt across the body, while also causing a knee-jerk or, rather, an elbow-jerk reaction in the arm.
Colloquially, most people knew the ulnar nerve as the funny bone at the elbow joint, a strange not-really-a-bone nerve that caused electric-like sensations and jerks in the arm.
That was why when Rui's first Sonic Bullet struck his opponent's ulnar nerve. Her body shuddered as the potent, precise, and accurate strike send electric-like shudders across her body her arm involuntary displaced itself in a jerk, consequently leaving her eyes exposed again.
Rui grinned, as a terrible sense of fear arose in his opponent.
