Somatic Referred Pain
Somatic Referred pain is a type of pain where the source is deep within a musculoskeletal structure, yet the perceived pain is in a different, often more superficial location. That is to say, the pain is experienced in an area that is different from the actual source of the painful stimulus. This may be due to the brain misinterpreting the signals coming from the painful stimulus and projecting pain to a different area.
To attempt to explain this mechanism simplistically: Nerves within our body are constantly sending signals up to the brain about what is going on in their location (it has been hypothesised that over 1 billion signals reach the brain each second!?!?!). These signals all converge in the spinal column on the way up to the brain, this can cause the exact location of where the signals are coming from to become misinterpreted by the brain. The result being that the brain responds with pain, but location it sends the signals back down to is inaccurate.
Somatic referred pain is often described as a dull, achy pain. It is often diffuse (i.e. not concentrated in a specific location) and tends to be more frequently experienced higher up, in the glutes/upper thigh. People experiencing this type of pain tend to have low back pain that is greater than their leg pain.
Different sources of spinal somatic referred pain could be:
Discogenic (pain is coming from a disc)
– Signs of discogenic pain include pain on flexion of the lower back, pain on coughing, sneezing, or straining.
Arthrogenic (pain is coming from a joint, i.e facet
joints)
– Arthrogenic low back pain tends to be exacerbated by extension or rotation of the spine.
Sacroiliac Joint – (the joint at which the spine
connects with the hip)
– Tends to be worse with prolonged sitting, standing or walking.
– Can be assessed successfully in clinic using a cluster of tests.
Non-spinal sources of referred pain
People with a corresponding limp are 7x more likely to have a hip issue than lumbar spine. This is also true of those experiencing groin pain. 72% of people with hip related leg pain report pain on pivoting movements.
Potential hip related sources of somatic referred pain:
Hip Osteoarthritis:
– Most prevalent in adults over the age of 45.
– Activity related joint pain.
– Some risk factors of hip osteoarthritis are: obesity, hypertension, smoking, cardiovascular disease. All of these factors increase inflammation throughout the body.
Greater Trochanteric Pain Syndrome:
– This term can include the issues of gluteal tendinopathy, bursitis, snapping hip.
– Symptoms include pain on activity and side lying that disrupts sleep.
– 1 in 4 women over 50 years old experience this.
– 45% of people with GTPS have persisted lower back pain
– Risk factors include, menopause, certain medications, load, past medical history.
Deep Gluteal Pain Syndrome:
– This related to a non-disc related entrapment of the sciatic nerve within the gluteal space.
– People often experience buttock pain, pain with sitting, pain on palpation of the buttock.
We can see from this blog that diffuse leg pain could be attributed to many factors, and it is important to assess carefully.
Hopefully, this post, expanding on the last blog, has been a useful break down of somatic referred pain. If you have any questions relating to any of the topics covered please get in touch HERE!
In the next post I will discuss Neuropathic causes of leg pain!
Stay tuned!
