Enthesopathy

If the condition is known to be inflammatory, it can more precisely be called enthesitis.

non granulomatous inflammatory changes at the entheses (attachment points of ligaments, tendons, or capsules on bones; the locus of involvement in AS) stimulates re-placement of ligaments by bone, ultimately resulting in osteoporotic VBs, calcified intervertebral discs (sparing the nucleus pulposus), and ossified ligaments, producing square-appearing VBs with bridging syndesmophytes, the so-called “bamboo spine” or “poker spine.” Extra-articular manifestations (EAMs) include anterior uveitis, inflammatory bowel disease (IBD), and psoriasis.