Introduction
Accidents, happen everywhere even at home from the simplest to the most dramatic.
When it comes to domestic accidents, the kitchen might be the most familiar scene, we are prone to various kinds of accidents in there ranging from a burn to a deep cut. It's no surprise how often accidents happen in the kitchen due to frequent contacts with hot and sharp things, sometimes without caution. Considering the major accidents that are likely to occur in the kitchen, the finger cut by knives is second most common.
Unfortunately, a few weeks ago I became a victim of this domestic accident. It's actually not the first time I ever had a knife cut though, but this particular cut kind of stands out lol I had to put it that way.
I don't think I am going to forget this experience in a hurry, It was on a very beautiful Monday morning, while I tried to fix up something little for breakfast and I had to slice onions, I wish I knew I was about to have a very horrible day. My knife has been kind of blunt for a while now and it was just perfect for me but then a friend of mine who stays with me had the knife sharpened over the weekend and I was aware of that but for some reasons on that fateful morning it totally skipped my mind maybe because I was in a hurry.
So, while I was slicing the onions and applying the same force I did when the knife was still blunt, somehow my left index finger got in the way and that was it.
I just had my deepest cut and the pain was excruciating, I immediately applied pressure to the cut finger in an attempt to stop bleeding which was very successful while I ran straight to a nearby clinic for treatment, on getting there luckily for me I was attended to immediately.
I was asked to ease the pressure by the nurse so that she can examine the extent of the cut, and when I did, even I couldn't believe it, it was deep, I could see my cut vein pumping blood like some water tap it was a horrible sight to behold I almost cut off the upper part of my left index finger. The nurse ensured I stopped bleeding and dressed the cut immediately and I went back home.
Most times when these knife cuts to the finger occur it is usually not so bad and would heal in a few weeks like in my case except that I discovered something strange as the injury healed off. First I noticed that I couldn't feel anything or even bend the injured finger but then, I was like how do expect I to do all of that with the bandage and all? I was hoping that in no time when the bandage is removed everything would return to normal, but then weeks passed and the injury had healed even faster than I expected but still, I couldn't get my feelings back lol and I still couldn't use the index finger. So many things I could easily do all of a sudden became difficult for me, even making this post.
What's with the index finger that makes it so important I asked myself?
I went back to the clinic where the cut was treated, and I explained the current situation to the doctor but I was told with time full functionality will be restored, that wasn't enough as I needed more answers. Haven made some research I discovered I had injured a branch of my median nerve.
Image created by me.
Take a look at the image above, that is me showing my left and right index finger and this is more than six weeks since I had my deepest cut but it is obvious that I still can't actually bend my left index finger like I do the right finger alike.
The median nerve or should I say the nervous system, in general, is quite fascinating, I mean in its function and importance.
I would keep on massaging my left index finger and do more vitamins as I was advised to do when I consulted @air-clinic the first and only online hospital on the blockchain.
In this post, I would be discussing deeply on the Median Nerve with respect to my present condition having realized how important it is.
I feel it's very important for us to catch up a bit on the basics of the nervous system before we get into the median nerve. This basic reminder will go a long way in helping us understand the median nerve even better.
The nervous system is a complex network of nerves and cells that transmit messages to and from the brain and spinal cord to various parts of the body.
The nervous system consists of both the central nervous system (CNS) and peripheral nervous system (PNS).
The central nervous system is divided into two major parts the Brain and the Spinal Cord.
The peripheral nervous system is also divided into two major parts the Somatic Nervous System and the Autonomic Nervous System.
For more on the nervous system in general Click Here.
The main focus of this post is going to be on the median nerve which is a major peripheral nerve of the upper limb.
It is noteworthy that the upper limb is one of the reasons our species has evolved to be so dominant. It gives us the ability to grip, throw and strike. Most of these functions we carry out using the upper limb won't be possible without the median nerve.
The median nerve gives us one very important function of life, and that is the ability to oppose our thumb which is important for precision handling and helps us perform lots of activities which includes writing, threading a needle etc. Take a second, pick up a pen and try to write, damn right that's your median nerve at work or imagine threading a needle. Humans are the only species on Earth with fully opposable thumbs all thanks to the median nerve.
Origin Of The Median Nerve
The median nerve licensed under Wikimedia (CC BY-SA 2.0)
The median nerve is derived from the unification of the medial and lateral cords of the brachial plexus. It forms from nerve roots originating at C5-T1.
After it's formation, the median nerve lies lateral to the axillary artery. It enters the arm and descends down the arm in a superficial course. Initially, it is lateral to the brachial artery but then as it descends it becomes medial.
Just before entry to the forearm, the median nerve courses between the tendons of the biceps brachii and brachialis. In the forearm, the nerve travels between the flexor digitorum profundus and digitorum superficials muscles.
The median nerve births two major branches in the forearm one of which is the anterior interosseous nerve which is responsible to supply deep muscle in the anterior forearm and the second is the palmar cutaneous nerve, this nerve Innervates the skin of the lateral palm i.e stimulates the skin or supply energy to the skin of the lateral palm.
The median nerve enters the hand through the carpal tunnel beneath the flexor retinaculum, it then divides to form two common palmar digital nerves:
• Recurrent branch – This branch Innervates the muscles of the thenar eminence which includes the Opponens pollicis, Abductor pollicis brevis and Flexor pollicis brevis (O.A.F).
• Palmar digital branch – This branch stimulates the palmar surface and finger of the lateral three and a half digit and also stimulates the lateral two lumbrical muscles.
This particular branch is very important considering the topic and the situation from which it was birthed, so I would throw more light here.
The palmar digital branch, in other words, gives out three different branches to the lateral one and a half digits, two out of the three branches goes to the thumb and the other branch goes to the lateral side of the index finger.
The branch that goes to the lateral side of the index finger is the actual branch of the median nerve that got damaged when I had the knife cut because as I mentioned earlier....
The palmar digital branch stimulates the palmar surface and finger of the lateral three and a half digit.
That also includes the index finger, and I also mentioned that I lost sensation at the upper part of my index finger and I also can't perform some functions with my index finger like bending it the way I used to or even attempt a pinch. All of are the responsibility of the palmar digital branch.
The palmar digital branch further divides into two branches, the medial and lateral branches and they both innervate the 2nd and 3rd interdigital clefts with adjacent index, middle and lateral half of the ring finger.
Functions of the Median Nerve
The Median nerve primarily provides motor innervation to the flexor muscles of the forearm and the muscles of the thenar eminence, by so doing controlling the coarse movements of the hand.
The median nerve does not have a voluntary motor or cutaneous function in the brachium. The median nerve is responsible for the cutaneous vascular branches that reach the brachial artery.
It innervates all the flexors in the forearm but the flexor carpi ulnaris and the part of the flexor digitorum profundus that supplies the 4th and 5th digits.
In the hand, motor innervation to the 1st and 2nd lumbrical muscles and the muscles of the thenar eminence are supplied by the median nerve. It supplies the muscles of the thenar eminence through a recurrent thenar branch.
The median nerve through its recurrent branch and palmar digital branch supplies motor innervation to the skin of the palmar side of the index, the middle finger and thumb, the nail bed and half the ring finger. This goes further to explain the loss of sensation in my index finger due to the cut.
The median nerve also supplies motor innervation to the lateral part of the palm through its palmar cutaneous branch. The cutaneous branch journeys near the flexor carpi radialis and then surficial to the flexor retinaculum in a fascial groove.
Median Nerve Entrapment Mononeuropathy
Neuropathy is quite a broad term referring to the clinical presentation of sensory dysfunctions which may lead to pain, paresthesia, numbness or even motor weakness in the expected distribution of a particular nerve.
When there is a dysfunction in one nerve group outside the brain and spinal cord take for instance the median nerve, it is called a mononeuropathy (peripheral neuropathy).
Neuropathy generally, usually occurs as a result of damaged nerve cells and injury (accident, falls, repetitive motion stress etc), happens to be the most common cause of this condition.
Median nerve entrapment mononeuropathy which could also be referred to as median nerve entrapment syndrome is a mononeuropathy that affects sensation in hand as well as the movement of the hand. This could result from compression of the median nerve in the elbow or distally in the forearm or wrist.
There are two most common median nerve entrapment syndromes which we are going to be looking at.
Carpal Tunnel Syndrome (CTS)
carpal tunnel syndrome licensed under Wikimedia (CC BY-SA 2.0)
The carpal tunnel is a narrow passage in the wrist formed by small wrist bones called carpal bones. The tunnel is roofed with the transverse carpal ligament which is a strong band of connective tissue.
The median nerve passes through the carpal tunnel at the wrist and goes into the hand as well as the nine tendons that bend the fingers and thumb. These tendons are called flexor tendons.
Carpal tunnel syndrome is a medical condition which occurs as a result of compression to the median nerve as it travels through the wrist at the carpal tunnel causing pain, numbness and tingling at the index finger, middle finger, thumb and at the thumb side of the ringer fingers.
This is almost descriptive of what am experiencing at the moment but no, mine is not a case of carpal tunnel syndrome and this is how I know. Firstly the numbness and tingling I feel at the upper part of my index finger aren't as a result of any form of compression at my wrist i.e the carpal tunnel and secondly the causes of carpal tunnel syndrome which doesn't include a knife cut at the index finger. So what causes the carpal tunnel syndrome? one might want to ask.
The carpal tunnel syndrome is quite common and occurs when tissues surrounding the flexor tendon swell causing the tunnel to be narrowed thereby putting pressure on the median nerve. These tissues are called synovium and they are responsible for lubricating the tendons, making it easy for us to move our fingers.
when the synovium tissues swell it occupies a larger portion of the carpal tunnel thereby putting pressure on the median nerve. This pressure on the nerve is the direct cause of pain, tingling, numbness, and weakness in the hand, experienced by a patient suffering from Carpal tunnel syndrome.
Quite a number of medical conditions have been associated with the carpal tunnel syndrome. Some common conditions include diabetes, trauma, arthritis, and obesity. Genetics also play a role here as the carpal tunnel may be smaller in some people.
Treatment of carpal tunnel syndrome is done either surgical or nonsurgical depending on the severity of the symptoms experienced. for mild symptoms, doctors are most likely going to recommend nonsurgical treatments at first.
Nonsurgical treatments may include wearing of brace or splint at night, this to help keep the wrist from bending while at sleep or even during the day, this is very useful because keeping the wrist in a neutral or straight position reduces pressure on the nerve in the carpal tunnel.
A rigid splint licensed under Wikimedia (CC BY-SA 2.0)
Also as a nonsurgical treatment, nerve gliding exercises may be helpful to some patients as they help the nerve move freely within the confines of the carpal tunnel. It is important that these exercises be done according to the recommendation by the doctor or therapist.
The use of nonsteroidal anti-inflammatory drugs(NSAIDS) and steroid injections are sometimes recommended to help relieve painful symptoms or calm a flare-up of symptoms, though their effect may be temporary.
Activity changes are also important in the treatment of carpal tunnel syndrome this is because the repetitive task at work or even recreational activities that cause the wrist to be flexed or extended may aggravate the symptom and thus changing or modifying these activities can help slow or stop the progression of the carpal tunnel syndrome.
Carpal tunnel release is the surgical procedure performed for carpal tunnel syndrome and there are two different techniques for performing this procedure both with the same objective to relieve pressure on the median nerve.
The objective of the carpal tunnel release procedure to relieve pressure on the median nerve is achieved by cutting the ligament which forms the roofs of the tunnel as mentioned earlier. The result of the procedure is an increase in the size of the tunnel which in turn decreases pressure on the median nerve.
carpal tunnel surgery under Wikimedia (CC BY-SA 2.0)
One of the techniques used in carpal tunnel release is the open carpal tunnel release. It is an open surgery where the doctor makes an incision in the palm a small one, from which he views the inside of the hand and wrist, and then divides the transverse carpal ligament (the roof of the carpal tunnel). This increases the size of the tunnel and decreases pressure on the median nerve.
Endoscopic carpal tunnel release is the second technique used in the carpal tunnel release procedure, in this case, two smaller incisions called portals are made on the hand by the doctor who then inserts an endoscope into the incision to see the inside of the hand. A special knife is then used to divide the transverse carpal ligament.
Anterior Interosseous Nerve Syndrome (AINS)
The anterior interosseous nerve is the largest branch of the median nerve, it branches out of the median nerve just below the elbow, and as mentioned earlier it is one of the two major branches of the median nerve in the forearm. It innervates the long flexor muscles of the thumb, index and middle finger as well as the pronator quadratus as it passes distally on the anterior interosseous membrane.
The anterior interosseous syndrome also called Kiloh-Nevin syndrome is a pure motor neuropathy in which damage to the anterior interosseous nerve causes pain in the upper forearm and sometimes elbow as well as impaired flexion of thumb, index and middle finger. AINS is mostly caused by transient neuritis, and in rare cases when compression of the anterior interosseous nerve happen. Although there are other numerous causes of the AINS which includes supracondylar fractures which are often associated with hemorrhage into the deep musculature.
Direct trauma from a penetrating injury such as a stab wound which could also cause nerve compression, is a common causative of the syndrome and patients may experience pain as well numbness.
AINS also occurs when the fibrous bands or arcuate (curved) ligaments entraps the median as well as the anterior interosseous nerves, in which case a patient may experience numbness as well as pain.
The anterior interosseous syndrome occurs without any sensory deficit although patients may experience a characteristic pinch deformity and inability to make a fist due to motor weakness and paralysis in the flexor pollicis longus, flexor digitorum profundus, and pronator quadratus muscles.
Anterior interosseous nerve entrapment has been quite a difficult clinical diagnosis owing to the fact that it is mainly a motor nerve, its syndrome is usually mistaken for finger ligamentous injury.
Just like the carpal tunnel syndrome, treatment of anterior interosseous syndrome may require non-surgical or surgical procedures depending on the severity.
Most cases of anterior interosseous syndrome improve spontaneously without the use of any surgical procedures.
Non-surgical treatments may include physiotherapy which should target specifically, the pattern of pain and symptoms. As non-surgical treatments, conservative management with rest, the use of analgesia (Steroids, Nonsteroids anti-inflammatory drugs) and splinting at in 90° flexion are also considered. Surgical decompression procedure will be considered if non-surgical treatment fails after 3 months.
The surgical procedure involves decompression of the anterior interosseous nerve an this can be achieved by tying off any crossing vessels, removal of any space-occupying lesion, separation of superficial head of the pronator teres and also by releasing the arch of flexor digitorum superficialis and lacertus fibrous.
It is very important that we understand the importance of nerves to our general well being, and thus the need to stay careful and avoid trauma to the nerves.
Let me share briefly a thought I had a few days ago. I just entered a tricycle on my way home from work at first it was just me inside, as usual, I was just flexing my left index finger which I injured trying to see if there have been any improvements in the nerve regeneration process and also just as a means to exercise the finger, suddenly the tricycle stopped and someone else joined and to my greatest surprise he had a bandage to the tip of his elbow, the bandage was still looking very new like he was just from the hospital. He had just been amputated from his elbow, I felt really sorry for him, considering how I feel haven injured a just a branch of the median nerve I couldn't even imagine what he going through. I kept thinking what even happens during amputation? how many nerves are severed and how does the brain even get to deal with that? if you've ever injured a nerve you might understand better why I asked myself those questions.
For a proper understanding of this post and in a bid to carry everyone along no matter your area of specialization I have taken out time to prepare a robust glossary on this post where all terms that might seem confusing have been well defined for everyone to relate. Do well to visit the glossary below.
References and Glossary
Vist the link below for all references, glossary and for more images on the median nerve.
References and Glossary
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