Pain within the area of the fourth lumbar root has been studied and interpreted partly as referred pain (in arthrosis deformans coxae) and partly as caused by direct disorder of the root (in disk herniation and osteoarthritic disorders in the spine). In 6 cases with pain similar to arthrosis deformans coxae the question of the cause of pain is undetermined.
Analyses of muscle tenderness, spontaneous pain and experimental irritation together with experimental anesthetizing of hip joints indicate that the pain in arthrosis deformans coxae can be interpreted as referred pain within, chiefly the area of the fourth lumbar root.
Rhizotomy of the fourth lumbar root in pain interpreted as referred pain within chiefly the distribution area of this root gave relief from pain in 12 of 14 cases. The pain is prone to recur. After an observation period of fourteen months there were satisfactory results in 6 of 14 operative