“…Muscular factors play a role not only in the acute episode of TTH. On the basis of numerous pain perception, imaging, pharmacological and longitudinal studies, it has been demonstrated that prolonged nociceptive input from peripheral myofascial tissues in subjects with episodic TTH can lead to sensitization of the central nervous system and in this way to transformation from episodic to chronic TTH (Bendtsen, ; Bendtsen and Jensen, ; Fernandez‐de‐Las‐Penas et al., ; Ailani, ; Chen, ; Cathcart et al., ; Bendtsen and Fernandez‐de‐la‐Penas, ; Bezov et al., ) (Fig. ).…”