ICD-10-CM > M00-M99 > M80-M85 > M85 > M85.4 > M85.43 M85.43 Solitary bone cyst, ulna and radius Non-Billable/Non-Specific Codes M85.431Solitary bone cyst, right ulna and radiusM85.432Solitary bone cyst, left ulna and radiusM85.439Solitary bone cyst, unspecified ulna and radius