Abstract The parent grant is a collaboration of two complementary research groups that is designed to spatially map the chondrocytes that form and maintain the human articular cartilage (AC) of a synovial joint which in this case is the knee. The Scripps component obtains and processes the experimental samples for detailed molecular expression studies. The UCONN component utilizes its skills in histological imaging of skeletal tissues to provide the spatial distribution of the cells that are identified by the molecular expression data using an RNA identification method called MERFISH. The activities proposed in this supplement expands the identification technology to utilize antibody binding to the proteins encoded by the genes (CODEX). The supplement will support the implementation of this antibody detection method to multiple targets so that groups of cells with a defined biological function can be identified and their location mapped to specific zone of the human AC. The two imaging techniques should be complementary and provide a high degree of confidence in patterns of distribution of functional groups of cells within the 3 zone of the AC. Eventually it will serve as the baseline for appreciating a disturbance in the patterns when the tissue is under a stress that can lead to the early stages of cartilage degeneration and the eventual onset of osteoarthritis.