TOPICS: Arthritis, HLA B27, axial skeleton, sacroiliitis, ankylosing spondylitis, sacroiliac joint, morning stiffness, bamboo spine, kyphosis, restrictive lung disease, aortitis, aortic regurgitation, anterior uveitis, reactive arthritis, conjunctivitis, urethritis, arthritis, Chlamydia trachomatis, achilles tendon, psoriatic arthritis, sausage shaped, nail pitting, pencil in cup deformity