poker back

spon·dy·li·tis de·for·mans

arthritis and osteitis deformans involving the spinal column; marked by nodular deposits at the edges of the intervertebral disks with ossification of the ligaments and bony ankylosis of the intervertebral articulations, it results in a rounded kyphosis with rigidity. Synonym(s): Bechterew disease, poker back, Strümpell disease (1)

poker back

Stiffness of the spine that may result from ankylosing spondylitis or related conditions.