Somatic referred pain is the pain that occurs from the stimulation of such structures that go beyond the location. Nociceptive back pain can refer to the buttocks and further down the lower limb. This does not involve stimulation of nerve roots — but rather facet joints, discs, the sacroiliac joints, etc.
The pain is usually dull, aching, gnawing, and is sometimes described as an expanding pressure. The areas are difficult to localize and can be widespread, although they settle in a relatively fixed location. Unlike radicular pain, the distribution won’t be dermatomal. The most common locations are the thighs and gluteal areas.
This is pain evoked by discharges of the dorsal root ganglion. It is most commonly caused by a disc herniation and subsequent inflammation of the nerve.
The pain is usually shooting, piercing, and/or stabbing in nature and will travel the lower limb in a band of no more than 2 to 3 inches wide. Against popular belief, however, it is impossible to determine the causative root of radicular pain.