ABSTRACT
This authors reviewed the radiographs of 20,057 patients with spinl radiculomyelopathy from April 1983 August 1990. The incidence and distribtion of the ossification of the spinal ligaments were analized as following. 1) The overall incidence of spinal ligaments ossification was 3.6% among 20,057 patients. 2) The most frequently occurs at lumbar area(67.1%), and then cervical(27.5%) thoracic(0.4%) area as in orders. 3) The OPLL was most common type(2.19%) of these spinal ligaments ossification, and then OALL(0.7%), OLF(0.24%) as in orders. 4) OPLL (1) OPLL was most frequent at lumbar area(58.6%) and then cervical(37.0%), thoracic(0.4%) area as in orders. (2) The cervical OPLL was commonly found at C5 & C6 area and morphologically, the multiple segmented type was most common then continuous type, mixed type and single segmented type in orders. (3) The multiple segmented type was more frequently found at upper cervical area, but the continuous type was more frequent at lower cervical area. 5) OALL (1) OALL was most frequent at lumbar area(86.0%) but thoracic(1.4%) and cervecal area(5.3%) were relatively low in frequency. (2) Of the lumbar OALL, the L4/5 area was most frequent site(37.8%) but the L3/4(25.3%) and L5/S1 area(24.5%) also had relatively high occurance rate. 6) OLF (1) OLF was most frequent at lumbar area(92.7%), but the incidence of OLF was relativerly rare at cervical(2.1%) and thoracic area(5.2%). (2) Of the lumbar OLF, the L4/5 area was most common site(33.1), but L5/S1 area had also high occurance rate(27.2%).