What you are seeing there is the top ejecta that possessed the Occipital plug and shot out over the top of the seat back followed by the heavier brain matter that slopped down in to the back seat and was seen oozing out by the medical witnesses...
ALL IN THE DIRECTION OF A REAR-EXITING OCCIPITAL WOUND AS SEEN AT PARKLAND...
This wound was clearly described by Clint Hill as he looked down in to it in the back of JFK's head...Hill was then forced to lie and his story progressed towards what Carrico also changed his story to...