Upper Body

Now that we have covered the tactical targets on the head, it's time to move to the upper body (from the neck down to the torso). There are a few areas that I have been taught about in a class, but I will mention other's I found on my own through rough-housing or from other site's and books that I have found over the many year's of interest in defense.

Let's start at the top, the spot I want to tell you about can be found in the center of the chest, between the two bones at the very top where the treachea can be found. The treachea is a dangerous spot to target as it controls the air going into the lungs so be wary of targeting this area.
Take your index and middle fingers (together for extra support) and curve them slightly and push them inward and downward, applying more pressure overtime will create increasingly more pain.

Moving down a bit to the sternum, here there are a couple of things that will work, if you have lip gloss stick or a flashlight (cylindrical), something solid that you can make a fist with with one end of the cylinder pertruding (about an inch), you can take this and rub the sternum straight up and/or down, if you don't have any tools availiable you can use your knuckles, using a tightly locked fist will still work.

Similarly, the knuckles or the cylindrical type tool can be used to rub the rib cage up and down.

Nerves

So the key to most these next areas, are to ether attack the muscle itself or the nerve that lies under or between the muscles.
The main nerves I will be talking about will be the Ulnar and Radial nerves. You can search for them if your truly interested in them, but the basic idea is that when these nerves are hit they create a pinch and inflict more pain as they are more directly connected to the brain and also, these nerves are used in motorary functions. You may have heard of them as being "pressure points".
These two nerves run all the way down from the brain to your toes, so that means everyone has them, the problem is that some people will have conditioned these areas to be more resillient or cover over the gaps with muscle. But never fear, as there are different types of people, there are different areas to target.
Ok, to start, keep in mind that the ulnar and radial nerves run down the inside and outside of the the body...not like veins, think of it as like a drawing of a human body, the outline of the body is approximatly where they can be found in most cases.

The top of the shoulder where trapezius (trap), connects to the arm can be impacted straight downward with a bottom of the hand (or a chop) to stun the hand from a tight grip.

This next one can be a little unorthodox, and smelly but when it's your head on the line, use whatever works...right? under the arm (armpit), with curved fingers, using the same method in the treachea target, hook inward and downward toward the center of the body. Aside from feeling uncomfortable the added pressure can potentially hit a nerve.

The arm has a few spots where the two nerves can be exposed.

First off, I will talk about the spot between the deltoid and the bicep, if you where ever into the punching games with "friends" this will sound familiar to you, if not let me explain. This game consisted of  two kids that would hit each other in the shoulder to show thier endurence of pain, it was a turn based process until one or the other could not continue and as a result they would be the loser...silly I know.
How this worked was a bit off from what we thought, as the target we would be aiming for was the deltoid itself as opposed to the opening between the muscles. Hitting the deltiod would still cause the arm to go numb over time but it was less effective as the target was an inch higher and covered with muscle, hence flexing would harden the muscle covering the nerve [...and is how you would win the punching game :) ].

These nerves continue on both the top and the bottom of the arm, remember the armpit? well the same nerve you targeted there also runs under the arm, between the bicep and tricep on the inside from the armpit right right down to the elbow (found on the opposite side of the deltoid).

The forearm is more particular in the exposure of these nerves, as the build of muscle can cover most of the area, but it's not impossible to get to. See on most of us, the wrist (underside) is difficult to build muscle that can cover over the entire nerve, so it is possible to impact the nerve from the wrist to about the center of the forearm. Also on the top of the arm there is and opening right where the two muscles overlap (also found at the center of the forearm).

The hand may be difficult to hit this nerve, as a cleched fist can cover the entire nerve in this area, but it can be found in the center between your middle and and ring fingers. Knuckles or a fist impact to the back hand can stun the fingers from a tight grip.