The mechanical and biological functions of musculoskeletal tissues are based on their structure, organization and composition. Maintenance of tissue integrity, acute changes with injury and repair, as well as progressive and chronic changes with aging and disease, can be evaluated and quantified on the sub-cellular, cellular, extracellular, and tissue level by histological techniques. Normal and pathological human tissues and animal models are widely used to study the cellular, extracellular, and tissue determinants of these processes. Thus, qualitative and analytical descriptions of key histological changes by standard and advanced staining techniques, and assessment and measurements of important histomorphological parameters in human tissue and animal models are at the foundation of examining critical questions in musculoskeletal health and disease. The overall objective of this Histology Core is to develop and apply a wide range of standard and innovative histological and histomorphometric approaches to evaluate musculoskeletal tissue structure and composition, and to provide training and funding for new projects and collaborations using these approaches. Due to their heterogeneous structures and compositions, musculoskeletal tissues present unique experimental and analytical challenges that require customized, sensitive and diverse histological assays. The PCMD Histology Core provides sophisticated expertise, and a suite of standard and novel tools and techniques, which are specially tailored for the complete range of musculoskeletal tissues, including intervertebral disc, bone, cartilage, fibrocartilage, tendon and muscle from large and small animal models, human tissue samples, and tissue-engineered constructs. Conventional techniques supported by the core include paraffin, frozen and plastic processing, embedding, sectioning and histochemical staining, as well as imaging and analysis, and more advanced and sophisticated techniques such as immunohistochemistry and histomorphometry. Additional new, cutting edge techniques will be added to the suite of core capabilities in this renewal. The Histology Core also provides educational programs for PCMD members and trainees through a range of mechanisms focusing on standard and advanced histological techniques, and their application to musculoskeletal research across a spectrum of healthy and disease conditions. With respect to service delivery, the core offers both full and self-service options, complemented by study design consultation and data interpretation to maximize the Core’s impact. A popular and fully subsidized protocol development and optimization service is offered to users to envision and jumpstart novel, application-specific histological techniques. Through this renewal, the Histology Core will continue to serve as a unique and indispensable resource for researchers at UPenn and in the wider community, catalyzing innovative and high impact musculoskeletal research, and stimulating c...