ECS is expressed in osteoblasts and osteoclasts. CB1 activation triggers osteoclast activity, while CB2 activation triggers osteoblasts. Polymorphisms in CB2 receptor raise the risk for osteoporosis. Some fraction of osteoporosis may be due to an endocannabinoid deficiency. The cartilage, tendons, fascia, and synovium all also express both CB1 and CB2 receptors. CB1 receptor activation at the neuromuscular junction has antispasmodic effects. Both CB1 and CB2 inhibit the release of interleukin beta and IL-1 from chondrocytes, decreasing cartilage breakdown. The ECS is beneficially involved in every step of the pathogenesis of degenerative arthritis, slow degradation of the cartilage, decreasing inflammation through activation of CB2 receptor on immune cells, and decreasing bone reabsorption via the same CB2 receptor activation. CB2 activation in the synovium was also capable of decreasing harmful inflammation. Here again, an ECS deficiency could increase the risk of arthritis.