Part 2 of 2: Is it Carpal Tunnel or Is it Something Else? Median Nerve Entrapment Sites
In part 1 of 2 of Is it Carpal Tunnel or Is it Something Else?, you were introduced to the common signs and symptoms of carpal tunnel syndrome. In part 2 of this blog, you will learn about other compression sites and conditions influencing the median nerve, which may resemble the signs an symptoms of carpal tunnel syndrome. Why is this important, you ask? First off, if you think you may have carpal tunnel syndrome, you want to be 100% certain. Second, you don’t want to receive treatment to an area of the forearm that may not be the area or reason for your health problem.
Of course, let’s get started with Forearm Anatomy!
Nerves of the forearm and hand originate in the neck area off the spinal cord. The spinal cord (the main cord coming from the brain) breaks down into many smaller branches (roots, trunks, divisions, and cords) of nerves that travel from the neck, through the shoulder, via the arm and down to the wrist and fingers. Nerves bring the ability to move and feel to our bodies. Specifically, the MEDIAN NERVE nerve is one of the nerves that provides movement and sensation to the forearm and hand.As you learned in the first blog, nerves can become compressed or squeezed by soft tissue such as muscles and ligaments. Moreover, compression of a nerve occurs due to various reasons such as sport injuries, repetitive strain/sprain, a tumor (very uncommon), etc. The nerve involved in carpal tunnel syndrome is the median nerve at the wrist. As you recall, when this nerve is squeezed around the wrist, a patient may experience frequent burning, tingling, and/or numbness in the palm of the hand and the fingers. Some sufferers say their fingers feel swollen and weak, even though little or no swelling is apparent. The symptoms often first appear in one or both hands during the night. The person may wake up feeling the need to shake out the hand or wrist. Continued carpal tunnel may result in decreased grip strength and muscles wasting at the base of the thumb. Furthermore, some people are unable to tell between hot and cold by touch.
In part 1, we gave the analogy that a traffic jam on a road resembles a compressed nerve. When a road is blocked with many cars, cars move slower than normal. A nerve that is squeezed or compressed transmits signals of movement and sensation slower to the hand. Now, to make things a little more complex, think of a busy highway….throughout the highway you have many areas in which traffic is slower than others. Let’s call these bottleneck areas. Throughout a stretch of road, there maybe multiple areas of blockages or bottlenecks. A nerve can also be blocked in various areas in the arm. Thus, it is important to examine the entire nerve pathway to be sure that no other areas are affected.
Ok, let’s get to the point….
Carpal tunnel syndrome symptoms appears similar to other compression syndromes/sites of the MEDIAN nerve. There are four regions where this blockage can occur below the shoulder.
1) Supracondylar process of the humerus and struther’s ligament (what a mouth full!):
The median nerve maybe compressed as it passes under a bony spur (normal variant) in the arm. This would cause weak hand grip, a hard time turning the forearm to a position in which the palm is facing down and it would also create tingling into the 1st to 4th fingers (never the 5th finger). The presence of having a difficult time turning the forearm into a position in which the palm is facing down is what differentiates this compression problem area from carpal tunnel syndrome.
2) The Lacertus Fibrosus:
The median nerve travels in front of the elbow (palm up side). The lacertus fibrosus is another area of compression and it is located just before the elbow. One must suspect that the lacertus fibrosis is the problem when pain is experienced in the forearm with resisted elbow flexion.
3) Pronator teres
The pronator teres is located just after the elbow on the palm up side of the forearm. This area of compression is VERY COMMON and confused many times with carpal tunnel syndrome. The nerve gets compression as it travels between the two pieces of PRONATOR TERES (Top and Bottom) muscles. When the muscle is tight and squeezes the median nerve, patients will complain of pain following resisted bending of the the long finger. Furthermore, the pronator teres muscles will be very tight and tender to touch and may produce symptoms down the forearm when touched. Usually, patients that do a lot of work with their hands and arms (plumbers, electricians and receptionists) experience this type of compression condition. Increased activity makes this condition worse. Furthermore, just like the compression areas above, a pronator teres compression will cause tingling to the 1st to 4th finger (palm side). Pronator teres compression is commonly confused with carpal tunnel syndrome!
4) Anterior Interosseus Nerve (Branch of Median Nerve)
The Anterior Interosseus Nerve can become compressed in the forearm (palm side up). It is important to note that compression of the median nerve has two presentations.
1) The pronator syndrome in which patients have pain and paresthesias mimicking carpal tunnel syndrome (above),
2) the anterior interosseous nerve syndrome in which patients have muscle weakness in there hand (thumb side).
If the Anterior Interosseus Nerve is involved, the patient will not be able to make the ‘OK’ sign with his/her thumb and index finger. Also, with the forearm flexed, the patient would have difficulty/weakness turning the palm from facing their torso to away from them.
How to you treat a median nerve compression?
Soft tissue therapy, electrotherapy and stretching often helps to relax tight muscle and decompress the tension placed on the nerve. In my practice, I apply a combination of chiropractic treatment modalities. I also have found acupuncture to provide pain relief as well periodically decrease the tingling sensations experienced. Acupuncture also helps by relaxing the tight muscles in the forearm, which is beenficial since it may reduce compression of the nerve.
Yes, I know, it is overwhelming and sometimes confusing to understand the course of a nerve. The point I am trying to get across is that the body is tricky and you must not jump to conclusions. If you or someone you know is experiencing tingling or has a decreased ability to move their forearm or hand, it is not automatically a case of carpal tunnel syndrome. You must screen whatever nerve is corresponding to the area of interest very carefully. If you have any questions, please feel free to comment and/or message me.
MEDICAL DISCLAIMER: The following information is my personal notes about this subject matter. It is intended for informational purposes only. Consult a health practitioner to help you diagnose and treat injuries of any kind.
Thank you for reading this post.
Dr. Luciano Di Loreto, HBSc., DC