We are all too aware that muscles, tendons, ligaments and bones can be injured and cause pain but unless it is really obvious we don’t seem to consider our nerves being painful. Normally, nerves just communicate pain and other sensations from nerve endings in tissues to the spinal cord and then to the sensory part of the brain. But when things go wrong they can actually become a source of pain as well.
Nerve pain is often described as aching, burning or tingly. It can sometimes be difficult to localise but often patients will show us where their pain is by drawing a line along the course of a nerve and describe it as travelling, shooting or moving. The pain is often felt in a different location to where the actual nerve injury or problem is located.
Nerves often become a source of pain when they are compressed as this impairs their mobility and also reduces their blood supply. Nerves are very blood thirsty tissues (the nervous system takes around 20% of the oxygen from our blood even though it accounts for only 2% of our body mass) and when this blood flow is impaired they will tend to complain. Some compression or entrapment occurs to a small degree naturally as nerves have to pass over and tunnel through and around other structures, often around large joints. Muscle stiffness will tend to pull on the nerves due to their connections with each other and after injury, when tissues are temporarily swollen or perhaps permanently thickened or scarred, this adds to the likelihood of nerve sensitivity. And it is not just pain that a nerve sensitivity can cause; it will tend to cause associate cramping, spasm or high tone in surrounding muscles, sensations of pins and needles or numbness and even impaired muscle function depending on what kind of nerve fibres are affected.
There are lots of very common examples of nerve entrapment syndromes that we see in clinic which have often been misdiagnosed and labelled as other tissue problems. For this reason, these problems often get treated in the wrong way and so become chronic as, inevitably, such treatments tend to fail. Many patients then resort to medical imaging such as ultrasound and MRI but scans often don’t show any evidence of entrapment and certainly don’t show nerve sensitivity. Diagnosis of nerve entrapment problems is reached from an expert clinical examination of the nervous system and at HFS Clinics the physiotherapists are all very familiar with testing the nervous system in this way. Here are some common examples of the nerve problems we see and the diagnoses that tend to get placed on them inappropriately.
Irritation of the sciatic nerve is very common as it passes through the buttock area behind the hip joint. As it leaves the pelvis, the sciatic nerve has to pass in front of some muscles but behind others and can become compressed or kinked in the process, often when these muscles are not working in a balanced way. This often causes pain in the buttock area around the compression site but also further along the nerve, perhaps in the hamstring or calf as the muscles surrounding the sensitised nerve tissue tend to tighten. It is rather like kinking a garden hosepipe; the first thing one notices is that water stops flowing at the end. Weakness may also result if the nerve fibres are severely compressed.
Pain around the Achilles tendon can actually be irritation of the tibial nerve as it passes through a narrow tunnel at the back of the ankle rather than pain from the tendon itself. The sural nerve also sits along the outside the Achilles tendon before passing along the outside of the heel and outside of the foot and can mimic Achilles tendon pain, often after ankle sprains.
The plantar nerves in the sole of the foot can also cause pain here as well as towards the inside of the heel and is often wrongly diagnosed as plantar fasciitis. We often see people who are complaining of on-going pain in the sole of the foot who have been seen by lots of different people with varying attempts at treating the “plantar fascia” rather than the plantar nerves.
So if your symptoms don’t quite fit the typical pattern…. could it be the nerves??
Nick Critchley is a Neuro-musculoskeletal Physiotherapist. His practice, HFS, have three clinics in London and provide physiotherapy to Team Run-Fast athletes.