Patellar position is related to the length of patellsr ligament. In patella alts associated with Osgood-Schlatter disease, the strong pull of well-developed qusdriceps muscle is probably the most important etiologic factor. In contrast, it is predicted that patells infera exists in parslytic quadriceps muscle. We measured the patellar position in 15 young adults of residual poliomyelitis whose unilateral quadriceps muscle power is zero to trace, from Jsnuary 1986 to August 1987. The result were as follows : 1. The greatest length of pstella in normal knees measured 4.51±0.27cm, but in poliomyelitis, 3.57±0.34cm. 2. Using Insall and Salvati method, in normal knees, measured 0.92±0.11, but in poliomyelitis, 0.63±0.12. 3. Using Blsckburne and peel method, in normal knees, measured 0.81±0.11, but in poliornyelitis, 0.56±0.13. 4. So, patella infera was observed in paralytic type of poliomyelitis and it is predicted that patella infera exists in paralytic quadriceps muscle.