Blood vessels are often overlooked in analyses of skeletal muscle biopsies. However, there are many vascular features in skeletal muscle biopsies that, when interpreted in the context of other histologic patterns and clinical history, provide useful information that allows muscle pathologists to narrow their differential diagnoses and provide more accurate guidance to treating physicians. Here, we provide a review of normal skeletal muscle vasculature with details of the ultrastructure of vessel walls. We discuss the vascular effects of factors common to many patients undergoing muscle biopsy, for example, diabetes mellitus, hypertension, and aging. We then discuss vascular findings relevant to diagnostic muscle biopsy evaluation, with current theories of pathogenesis and detailed descriptions of the important features.