Basics of polymyalgia rheumatica. Polymyalgia rheumatica (PMR) is a disorder that causes stiffness and aching that begins in the neck, shoulder and hip areas. It is not known whether it is a disease of the joints muscles or arteries.However it is thought that inflammation in these areas leads to pain and stiffness.Incidence.olymyalgia rheumatica (PMR) is a disorder that causes stiffness and aching that begins in the neck, shoulder and hip areas. It is not known whether it is a disease of the joints muscles or arteries. However it is thought that inflammation in these areas leads to pain and stiffness. Incidence.
There are two main types of volcanic eruptions: Explosive and Nonexplosive eruptions.he types of volcanic eruptions are magmatic, phreatomagmatic, and phreatic. For a description of each type and different styles of each, refer to the link below.
1 Two years into its life, pyroclastic activity began to wane, and the outpouring of lava from its base became its primary mode of activity. 2  Eruptions ceased in 1952, and the final height was 424 m (1,391 ft). 3  This was the first time that scientists are able to observe the complete life cycle of a volcano.here are two types of eruptions in terms of activity, explosive eruptions and effusive eruptions. Explosive eruptions are characterized by gas-driven explosions that propels magma and tephra. Effusive eruptions, meanwhile, are characterized by the outpouring of lava without significant explosive eruption.