What does it mean when you twitch in your sleep?

Myoclonus: This is likely to be a normal event. The sleep activity is divided in non-rem ( rapid eye movement) and rem sleep statges. Non-rem sleep is further devided in 4 stages (1-4) based and the amount of slowing if the electrical activity of the brain. It is common, as we transition from one stage to the next, a small and brief jerky movement may occur. This is entirely normal.