ENGINEERING THE HAND-PART 2

As some of you may know I recently suffered an ischemic stroke that affected my right hand. The resulting condition was that I had no strength in, or control of, any part of my right hand. I had no control over my fingers or thumb or any part of my palm. It was as if I had a rag mop suspended at the end of my arm. Being right-handed that meant I could not even hold a pencil or pen, let alone sign my name.

An ischemic stroke of the brain is caused by narrow arteries that severely reduce the flow of blood to the brain and are often caused by blot clots that form either in the arteries leading to the brain, or develop in other blood vessels prior to entering the blood stream and head towards the brain. Clots are formed from fatty deposits in the blood known as plaque. Whenever blood is restricted to the brain the result is that cells die. The condition is illustrated in Figure 1.

Figure 1

What I found most amazing was that the stroke I suffered had absolutely no effect on any other part of my body. Thankfully, I had no face drooping, arm or hand numbing or slurred speech. My wrist, arm, and shoulder all worked normally. I had no loss of touch sense or the ability to feel pressure, pain, or temperature in that hand. I just could not use the hand for any type of grasping, lifting, or movement.

Since I knew that I had likely experienced a stroke, I was quickly (within a few hours of the stroke event) at a hospital and was treated with an intravenous application of a special kind of blood thinner. Then I was placed in a hospital bed where I was carefully watched for 24 hours for possible side effects of the blood thinner. I was told that the most serious side effects could cause fatal issues with the heart. The diagnosis of an “ischemic stroke involving the left frontal lobe precentral sulcus close to the vertex” was made after an MRI of my brain the next day. See Figure 2 for the terminology.

Figure 2

The good news is that after about six weeks of occupational therapy I had regained almost all of the strength and dexterity in my right hand that had been lost. While medical personnel involved in my case were very aware of the condition and the ability of the body to recover from the condition, they did not share with me how they thought the recovery was actually accomplished. In the rest of this article I will provide a summary of what I found out about this recovery process.

The two primary parts of the body involved in my condition were the hand and the brain. As I explained in the article “Engineering the Human Hand-Part 1” and as described in hundreds of anatomy books and medical articles, an immense amount is known about the structure and detail of the hand. One new thing I discovered was that the hand is capable of 58 distinct movements. This amazing dexterity of function is accomplished with the help of muscles in the forearm and the wrist. (Please see figure 3 below.) In the case of my stroke I could sense no problem with any of the muscles or tendons in my arm or wrist. It was as if the connection of my arm to my hand had been physically severed at the wrist. Of course, that was not the case at all.

Figure 3- Muscles & Tendons of the Hand

Somehow my brain still remembered how to accomplish the 58 distinct movements and had a way to reconnect the circuitry in order for there to be a recovery of the use of my hand. The process of recovery was a matter of repetition of motion (exercises) for strength and dexterity. In my case probably 50% recovery took place in the first 7 to 10 days. Then the process became much slower with slight improvements each day. All experts seem to agree that the control center location for the right hand is in the left side of the brain.

Let’s look at some of the information I found out about the relationship of body function to control locations in the brain. While there are lots of medical experts on the brain they do not all agree about the details. I expect that is due to the complexity of the brain, an organ that has a complexity several orders of magnitude greater than, say, the hand. One thing they do seem to agree on is that there are areas of the brain that have been identified to usually control certain aspects and functions of the body. Figures 4 and 5 express the generality of that idea.

Figure 4

Figure 5

In regard to the brain’s control location for the right hand, I found one article that indicated that there were areas on the left side of the brain that have been identified as capable of controlling the right hand and as seen in Figure 6.

Figure 6

Notice that for the fingers the control areas are painted red in figure 6. I was not able to determine what the researchers thought about how much of the area was able to control the fingers or if different areas were for specific fingers. Perhaps one could conclude that the brain could adapt various areas to connect to various functions depending on the situation for each hand on each body. My conclusion is that it would be easy to think that the engineering complexity of this brain-to-hand connection is still way beyond human understanding.

In another article I learned that people who have had their hands amputated even decades previously still could maintain the representation of their hands in their brains. The researchers used a powerful MRI scanner on the brains of two people who were missing a limb for over 25 years and who still experienced phantom sensations of their limbs. They also scanned the brains of eleven volunteers with both arms intact. While inside the MRI machine the participants were asked to move their fingers one at a time. The results showed that the primary somatosensory cortex got activated in a similar pattern with both groups. That is, the volunteers who had no hands activated their brain areas the same as those with hands, although to a reduced amount.* See Figure 7 for an illustration of the results.

Figure 7

The importance of these findings to the researchers was that it gave them valuable information about how future prosthetics might be more effectively engineered. The importance to my research is that it seems to reinforce the fact that the brain has been engineered with an amazing ability to remember and adapt to accidents and disease that disrupt the original brain control of limbs and hands.

Why would that type of engineering be surprising regarding the amazing Creator God of each human?  It would not. For you created my inmost being; you knit me together in my mother’s womb. I praise you because I am fearfully and wonderfully made; your works are wonderful, I know that full well. My frame was not hidden from you when I was made in the secret place, when I was woven together in the depth of the earth. Your eyes saw my unformed body; all the days ordained for me were written in your book before one of them came to be. (Psalm 139:13-16.)

I do not know what the result would have been if I had not gotten to the hospital quickly. Nevertheless, I do thank God for engineering my body with the ability to adapt to this condition, and for providing me with the doctors and other medical personnel who knew how to assist in the process.

Thank you, Lord Jesus!

J.D. Mitchell

*Medical Tech News online, September 6, 2016.

 

 

 

 

 

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