EMCN (endomucin) is an endothelial sialomucin expressed on specialized bone vessels that plays a critical role in coupling angiogenesis with osteogenesis. EMCN is a marker of type H vessels (CD31hiEMCNhi), a vessel subtype identified by high co-expression of CD31 and endomucin 1. These type H vessels possess the intrinsic ability to induce bone formation and are essential for skeletal homeostasis 1. Mechanistically, EMCN expression is regulated by multiple signaling pathways including SLIT3 secreted by osteoblasts 2, PDGF-BB from preosteoclasts 3, and miR-497~195 cluster in endothelial cells 4. EMCN also participates in HIF-1α and Notch signaling to maintain endothelial function 45. In inflammatory conditions, EMCN upregulation prevents lymphocyte recruitment 5. Clinically, EMCN is relevant to bone pathologies including osteoporosis, fracture healing, and periodontitis. Reduced CD31hiEMCNhi vessel abundance correlates with age-related bone loss 4. Therapeutic strategies targeting SLIT3, PDGF-BB, or miR-195 pathways to enhance EMCN+ type H vessel formation show promise for treating osteoporosis, fracture healing defects, and periodontal disease 245.