It is known that nociceptive afferences in visceral pain and visceral disorders increase
sensitization in subjects suffering from fibromyalgia. These patients use to present visceral
comorbidities. Those comorbidities include that of peridiaphragmatic organs, which are
supplied by the phrenic nerve among other innervations. It is known that peridiaphragmatic
organs trigger referred pain in the neck area, via the phrenic nerves. So, the phrenic
nociceptive afferences can be contributing to enhance the state of sensitization in
fibromyalgia. This study aims to analyze the ability of phrenic nerve infiltration to
diminish sensitization in subjects suffering fibromyalgia, by means of a randomized
controlled trial.