The periodontal ligament serves primarily a supportive function by attaching the tooth to the surrounding alveolar bone proper.This function is mediated primarily by the principal fibers of the periodontal ligament that form a strong fibrous union between the root cementum and the bone.The periodontal ligament also serves as a shock-absorber by mechanisms that provide resistance to light as well as heavy forces.inally, the periodontal ligament provides a nutritive function that maintains the vitality of its various cells. The ligament is well-vascularized, with the major blood supply originating from the dental arteries that enter the ligament through the fundus of the alveoli.