ICD-10-CM > G00-G99 > G50-G59 > G56 > G56.2 G56.2 Lesion of ulnar nerve Non-Billable/Non-Specific Applicable To Tardy ulnar nerve palsy Codes G56.20Lesion of ulnar nerve, unspecified upper limbG56.21Lesion of ulnar nerve, right upper limbG56.22Lesion of ulnar nerve, left upper limbG56.23Lesion of ulnar nerve, bilateral upper limbs