In their focus article, Simone, Marchettini, and Ochoa have summarized their findings on the receptive field properties of deep, somatic, slowly conducting pri mary afferent axons and have correlated these prop erties to the sensations of deep pain in their human subject population. They arrive at three main conclu sions from these findings: 1. The most relevant stimuli for exciting muscle noel ceptors are mechanical and chemical stimuli. 2. Only one quality of pain sensation, cramping pain, arises from skeletal muscle regardless of the type of nociceptors excited. 3. Temporal summation accounts for diffuse, poorly localized muscle pain. These conclusions are modest and clearly supported by the data, and are already accepted by most clini cians and researchers who have studied deep, somatic nociception. The article, however, could provoke a more lively discussion if the authors had pointed out issues that have not been resolved by past studies; these unaddressed issues have considerable clinical impor tance. Many (but not all) of these issues could be inves tigated with the techniques the authors are currently using. These issues are outlined below.