Figure 2.

Hypothesis for a differentiation cascade between joint stem cells. The infrapatellar stem cells (IFP) would be divided into a perivascular (pericytes) and an adventitial population, with the pericytes being the most naive ones. Those would differentiate into synovial membrane stem cells. These can migrate into the synovial fluid, giving rise to synovial fluid stem cells, which would attempt to heal damaged cartilage. Dashed arrows represent more hypothetical relationships here proposed, while full arrows represent more proven ideas in the literature. This image was made using https://MindTheGraph.com.