<prompt> 40yr old male patient having pain with daily morning stiffness of spine for 30 minutes and reduced chest movements. Most probable diagnosis isAnkylosing spondylitisRheumatoid ahritisGouty ahritisOsteoahritis  <response>: The information in question are 40yr male Morning stiffness in spine Limited chest expansion all fit into clinical criteria for diagnosis of Ankylosing spondylitis x ray of ankylosing spondylitis -BAMBOO SPINE AS is a chronic, progressive immune-mediated inflammatory disorder that results in ankylosis of the veebral column and sacroiliac joints . The spine and sacroiliac joints are the common affected sites -- Chronic spinal inflammation spondylitis can lead to fusion of veebrae ankylosis . Characteristic Pathologic Features : Chronic inflammation in: - Axial structures sacroiliac joint, spine, anterior chest wall, shoulder and hip - Possibly large peripheral joints, mainly at the lower limbs oligoahritis - Entheses enthesitis Bone formation paicularly in the axial joints Axial manifestations: Chronic low back pain With or without buttock pain Inflammatory characteristics: - Occurs at night second pa - Sleep disturbance - Morning stiffness Limited lumbar motion Onset before age of 40 years Refer maheswari 9th ed 