The word "articular" refers to something related to or involving joints, especially in the context of bones. It describes the movement or structure of the joints where bones connect to each other. Full definition
The ends of each bone are covered with a thin layer of cartilage called articular cartilage. (sunnysidevetclinic.com)
[69] Natural synthesis of glucosamine occurs in the extracellular matrix of articular cartilage in joints. (en.wikipedia.org)
Chupkaornis has a unique combination of characteristics: finger - like projected tibiofibular crest of femur; deep, emarginated lateral excavation with the sharply defined edge of the ventral margin of that the thoracic vertebrae (those vertebrae in the upper back); and the heterocoelous articular surface of the thoracic vertebrae. (sciencedaily.com)