What are symptoms differences both common carotid arteries are compressed from that when both jugular veins are compressed?

One Hurts: When you compress both carotids, you only have two tiny arteries ("vertebrals") left supplying the whole brain. Ergo, you hit the ground unconscious. If the compression isn't relieved, you die fast. The veins are more compliant, but less redundant. Compression of the jugular leaves the brain with no backup drainage. You'll get a phenomenal headache as pressure builds up, then something will pop.