Articular structures include joint capsule and articular cartilage, the synovium and synovial fluid, intra-articular ligaments and juxta-articular bone o Articular disease involves: ▪ Swelling ▪ Tenderness of the joint ▪ Crepitus ▪ Instability “locking” ▪ Deformity ▪ Limits active and passive range of motion due to stiffness or pain • Extra-articular structures include periarticular ligaments, tendons, bursae, muscle, fascia, bone, nerve and overlying skin o Extra-articular disease involves: ▪ “point of focal tenderness in regions adjacent to articular structures ▪ Limits active range of motion ▪ RARELY causes swelling, instability, joint deformity Know the sources of joint pain (pg. 627 algorithm) • Nonarticular conditions: trauma/fracture, fibromyalgia, polymyalgia rheumatica, bursitis, tendinitis • Intra-articular (acute, < 6> 6 weeks): chronic inflammatory arthritis vs chronic noninflammatory arthritis o Chronic inflammatory arthritis with 1-3 joints involved: ▪ Indolent infection ▪ Psoriatic arthritis ▪ Reiter syndrome ▪ Periarticular JA o Chronic inflammatory arthritis with >3 joints involved: ▪ Psoriatic arthritis or Reiter syndrome (no symmetry) ▪ rheumatoid arthritis if not RA then