hyperbaton

An inversion of the usual or logical order of words or phrases, for emphasis or poetic effect.

In real life we often see a man under the influence of rage, or fear, […] begin a sentence, and then swerve aside into some inconsequent parenthesis, and then again double back to his original statement […]Now the figure hyperbaton is the means which is employed by the best writers to imitate these signs of natural emotion.

Adding a word or thought to a sentence that is already semantically complete, thus drawing emphasis to the addition.