ICD-10-CM > M00-M99 > M65-M67 > M66 > M66.3 > M66.35 M66.35 Spontaneous rupture of flexor tendons, thigh Non-Billable/Non-Specific Codes M66.351Spontaneous rupture of flexor tendons, right thighM66.352Spontaneous rupture of flexor tendons, left thighM66.359Spontaneous rupture of flexor tendons, unspecified thigh