Phones, Pockets and Pain

This post is in response to a question from Rich:
What are your thoughts on the effects of cellphones on our bodies? I’ve been having issues with my right hip flexor for a year. It obviously gets better when I do my stretching and exercises, but I wondered if the fact that I keep my iPhone in my right front pocket might play a role, since the discomfort emanates from the same place that my phone sits in my pocket. Have you read anything that has influenced where you keep your phone?
(I’m not talking about the structure of the phone causing discomfort. I’m wondering about the electronics within the phone…). The pain is a tension that runs up my IT band and then makes a right angle turn across the front of my quad at the place where my pants crease when I sit. Then occasional dull aching in that area. If I had my phone in my pocket, it would press on that area when I sit. (I take my phone out before I sit, btw.)
Hi Rich:

Thanks for writing. I will confess right away that I had to do more than my regular amount of sleuthing to get at this question which is interesting for a couple of reasons: one of them being that almost immediately after I received your question, a massage client asked a question about a nearly identical pain, but did not mention where he carried his phone, although he had a very tight iliacus and psoas muscles. I will come back to that in a bit. Another thing that is interesting about your question is the nature of pain. Pain has many possible inter-related causes, and is a complex affair, related to some kind of stimulus that is damaging or has the potential to damage tissues, but also related to perception, mood and many other factors which I will not really deal with in this post. Additionally, pain in one part of the body might be caused by a problem in another part of the body altogether, and this is known as referred pain. Your question asks in essence, might it be the electronics of the phone causing the pain and not the phone’s physical size and presence? I think this is a pretty reasonable question. In all instances, I should say before I get down to brass tacks, if pain is persistent, consult your medical professionals.

The easiest way to find out the answer to your question would be to take a 1200 people, stick working cell phones in the pockets of 400, just the active electronic bits in the pockets of 400, and disabled cellphones in the pockets of the remaining 400. Then have half of each of those groups put the stuff in their left pocket, and half put the stuff in their right pockets and find out who complains after a year and what side. It might be tough to get ethics approval because we aren’t really allowed to intentionally put people at risk. No one has yet done this study, so we will have to go with the existing research to see if we can figure out an answer.

The pain you describe corresponds with the location and sensations related to the lateral femoral cutaneous nerve (LFCN). The LFCN emerges from your spinal column around the level of the second and third lumbar vertebrae, dives between the quadratus lumborum and the psoas muscle, goes behind your guts, down across the front of the iliacus muscle (which lines the inside of your iliac bone), but underneath the sheath of fascia that covers that muscle. It then goes underneath the anterior superior iliac spine to emerge from under your inguinal ligament, over top of, or sometimes even through your sartorius muscle, and then under the fascia latae of the thigh. The take home message, is that the LFCN does a lot of weaving under and over stuff. The image below from Gray’s Anatomy shows where the LFCN emerges from under the inguinal ligament, which I will talk about more below. When your cell phone is in your front pocket, it is probably pretty close to the LFCN.

Looking up the right side of the pelvis from underneath. The lateral cutaneous femoral nerve is the small yellow structure on the left, just above the iliacus muscle. The big round structure is the socket of the hip joint (Gray’s Anatomy).

Part of the problem of answering your question is that cell phones are really too new and too rapidly changing in terms of size, shape and internal components to get a consistent read on what problems they might cause from either a mechanical or electronic standpoint. Cell phones only became pocket-sized in the mid-90s, and since 2002, smart-phone use has climbed from just over 50% to 90% of American adults owning one (http://www.pewinternet.org/data-trend/mobile/device-ownership/). This all means we don’t have a long list of case-studies to draw information from. What we do know radiation-wise is that while a cell phone is in your pocket in the on position, it will ‘ping’ nearby towers intermittently to let the network know where it is so that it can receive incoming calls. This will generate tiny amounts of radiation in the radio frequency. Talking on the phone itself generates a greater amount of radio frequency radiation as would happen if you used either a wired or bluetooth headset with the phone in your pocket. What we need to know about for your question is if the cell phone’s radio frequency could produce damage to nerves that could induce the perception of pain.

Radio frequency radiation might potentially cause damage to nerve cells due to heat, or by the disruptive effects of the radiation itself. Because we typically use cell phones next to the brain, which is a big, sensitive group of neurons, most studies with cell phone radiation focus on that structure. Quite a number of experiments have been done with cell phone frequency radiation and rodents. The results are variable, with some studies showing damage to the DNA of nervous tissue (Diem, Schwartz, Adlkofer, Jahn & Rudiger, 2005), and other studies saying there is no damage (Utteridge, Gebski, Finnie, Vernon-Roberts, & Kuchel, 2002). (Of course the real problem with cell phone use in mice is the roaming fees.) In humans some studies show a link with increased brain cancer risk in long-term cell phone use (Khurana, Teo, Kundi, Hardell & Carlberg, 2009), but other studies do not show this link (Lajavaara, Schuz & Swerdlow, 2011). There have only been a few studies on cell phone radiation and thinking, but nothing conclusive. More to the point, there is no direct evidence at this moment that placing a phone next to your brain changes the way you perceive pain, and besides, your question is about putting the phone in your pocket.

Radiation can certainly cause damage to peripheral nerves (nerves outside the brain and spinal cord) resulting in pain. Such damage is found at times in cancer patients who receive radiotherapy to treat the cancer (Stoll & Andrews, 1966). However the type of radiation for cancer treatment is typically x-rays, gamma rays or some form of particle radiation, which is at a much, much higher energy than radio frequency, and the focus is remarkably tight and concentrated. In comparison, placing a phone in your pocket would produce very small amounts of radiation, would be diffuse, and would differ from day to day because of differences in the placement of your phone and your clothing.

So in the end it is possible that a cell phone’s radiation could cause the pain you describe, but I think it is unlikely. Which brings me back to my client. After I got your question, I called him to ask about where he carries his cell phone – same or opposite side of the pain. Turns out, he doesn’t carry it in his pocket at all. Which made me wonder if something else was going on.

There is literature about a condition causing a very similar pain to yours (and the pain of my client). It is called meralgia paresthetica, which pretty much means ‘thigh pain felt in a weird place’.  Meralgia paresthetica is a painful, burning, muscle aching or sometimes even numb feeling on the outside of the thigh, or along its crease, caused by a compression or entrapment of the LFCN. As mentioned before, the LFCN emerges from under the inguinal ligament which runs from the Anterior Superior Iliac Spine of each side of your pelvis, down to the pubic bone. Its big job is to keep your nerves and muscles and other leg bits from blobbing out all over the place. The inguinal ligament is what causes the appearance of the ‘fold’ at the top of your thigh (exactly where your pants crease), showing the division between your torso and your leg. Sometimes through sudden weight gain, or swelling to the tissue behind the inguinal ligament things get pressed up against it, causing a pinching or discomfort. My client, for example, had very well-developed hip flexors, particularly the iliacus and psoas muscles which were also very tight. In fact, in some people you can induce a ‘pinching’ sensation at the inguinal ligament by bringing the hip into extreme flexion, since the tissues behind are being pulled up against the ligament. In my clients with such pinching (and in myself as well), I can alleviate the pinching in extreme flexion by thoroughly stretching the hip flexors.

While the LFCN could be compressed anywhere along its length, the most common location of entrapment is where it exits the pelvis (Grossman, Ducey, Nadler & Levy, 2001). The inguinal ligament is so prominent in anatomical causes for the condition that some surgeons have developed a method of relieving meralgia paresthetica by surgically loosening the ligament (Alderich & van den Heever, 1989). And that brings us back to the phone in your pocket, which led me to think of the article ‘Meralgia Paresthetica from a Wallet’ (Orton, 1984) in the Journal of the American Medical Association. In the abstract Orton says ‘I noticed an aching, burning sensation along the left anterolateral thigh on the side of the wallet. It also was worse while driving any distance.’  The condition has also been induced by tight pants (Boyce, 1984). Depending on the way the nerve is situated, it is conceivable that the condition could be induced by any pressure along the inguinal ligament, either from pressure directed inward from the outside by clothing, wallets or phones, or from pressure directed outward from the inside, by weight gain, pregnancy or big, tight, developed iliacus muscles.

There are completely different possible causes for your pain that have nothing at all to do with rectangles or electronics in your pockets (What has it got in its pocketses?) or even with meralgia paresthetica, so I am not saying you have cellphone-induced meralgia paresthetica (because I am not the right kind of doctor to make a diagnosis), but from all evidence it seems much more likely than a nerve problem caused by radiation. And this might be true even though you remove the phone when you sit, since any irritation  at all to the LFCN could be sufficient to cause the pain.

The best thing to do in either case is to take your phone out of your front pocket, which will prolong the life of your phone and get its electronic and mechanical influence, if any away from your body. Time will tell what kind of effects these devices have, and it won’t hurt to show a little caution. Also continue to stretch your hip flexors using postures like the yoga low lunge. Even if the cause is completely different, we spend so much time sitting that such a stretch will have benefits that are well worth your time, especially after a long drive.

cheers,

Doctor Blake