Fig. 1

a Pelvic radiograph revealing bilateral sacroiliac, and left hip joints with sclerosis of articular surface, narrowing of joint space, and disappearance of partial joint space (arrows). Osteonecrosis of the right femoral head is also found. b Lumbar vertebra radiograph showing typical “bamboo spine” (arrow), narrowing and disappearance of the left sacroiliac joint space, and sclerosis of the articular surface. c Lateral view radiograph of lumbar vertebra showing reversal of the physiological curve of lumbar vertebra. d Thoracic spine radiograph revealing thoracic spine kyphosis, multiple synostoses in the margin of the vertebral body, and “bamboo spine” (arrow). The image is in accordance with the manifestations of ankylosing spondylitis (AS). e, f Enhanced thoracolumbar magnetic resonance imaging (MRI) revealing an extensively abnormal signal (e–f, arrows) at T9–10, destruction of the thoracic vertebra (e–f, arrows), and bleeding changes (e, arrow) within the lesions with intervertebral disc denaturation. Discontinuity of T9–10 interspinal ligament with cord-like high signal intensity in T2-weighted image; rupture of the interspinous ligament was suspected. g, h Pathological examination of the soft tissue around the abnormal thoracic vertebra revealing the presence of necrosis, dead bone fragments, proliferation of granulation tissue, fibrous connective tissue accompanied by focal hemorrhages, and inflammatory cell infiltration, with no tumor cells, no focus of spinal tuberculosis, and no fungi observed using a light microscope (hematoxylin and eosin, original magnification ×40). i (Graphical abstract) Schematic diagram of intercostal neuralgia caused by vertebral fracture. Fracture of the thoracic spine results in compression of the spinal cord and spinal nerve root, the latter of which extends out via the intercostal nerve