Atherosclerosis is the primary underlying disease in over 90% of those with peripheral vascular disease. A small but significant subset of patients with peripheral vascular disease, however, are affected by illnesses or conditions quite dissimilar from arteriosclerosis. Although the pathophysiology of vasospastic disorders generally is unknown, most display alterations in the normal function of the sympathetic nervous system. Many of these conditions are no less incapacitating than limb-threatening atherosclerotic arterial occlusions, yet they frequently are overlooked, neglected, and misunderstood. Such circumstances can cause a delay in diagnosis and optimal management. Many patients with Raynaud's syndrome do not have an underlying associated disease, whereas the presence of this syndrome may be one of the first symptoms of a more systemic disease. The posttraumatic pain syndromes remain poorly understood and, therefore, create a delay in diagnosis and proper treatment. For these reasons, we have prepared this 3-part review of nonatherosclerotic diseases and vasospastic conditions. Part 2 will focus on noninflammatory, nonatherosclerotic vascular disease, and the final section will cover vasospastic conditions.