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  5. Mononeuropathies of upper limb (G56)

Mononeuropathies of upper limb (G56)

ICD-10 code section G56 covers mononeuropathies of the upper limb, which are conditions involving nerve damage or compression in one or both arms. Key codes in this section specify nerve issues such as carpal tunnel syndrome and lesions affecting the median, ulnar, or radial nerves.

This set of codes is used to classify distinct nerve problems in the arm, including the well-known ICD-10 code for carpal tunnel syndrome (G56.0). Synonyms like median nerve compression and anterior interosseous nerve entrapment help clarify when to use these codes. Other codes identify damage or entrapment of the ulnar and radial nerves, with detailed options for right, left, or bilateral limbs (for example, G56.21 for right ulnar nerve lesion). Additionally, causalgia (complex regional pain syndrome Type II) of the upper limb is included (codes G56.40–G56.43).

For medical coders, recognizing the specific nerve involved, the affected side, and utilizing synonyms such as “pronator syndrome” or “Tardy ulnar nerve palsy” can guide accurate code selection. This section ensures precise coding of upper limb nerve conditions, facilitating appropriate diagnosis and treatment documentation.

  • Diseases of the nervous system (G00–G99)

    • Nerve, nerve root and plexus disorders (G50-G59)

        • Mononeuropathies of upper limb (G56)

        • G56 Mononeuropathies of upper limb
        • G56.0 Carpal tunnel syndrome
        • G56.00 Carpal tunnel syndrome, unspecified upper limb
        • G56.01 Carpal tunnel syndrome, right upper limb
        • G56.02 Carpal tunnel syndrome, left upper limb
        • G56.03 Carpal tunnel syndrome, bilateral upper limbs
        • G56.1 Other lesions of median nerve
        • G56.10 Other lesions of median nerve, unspecified upper limb
        • G56.11 Other lesions of median nerve, right upper limb
        • G56.12 Other lesions of median nerve, left upper limb
        • G56.13 Other lesions of median nerve, bilateral upper limbs
        • G56.2 Lesion of ulnar nerve
        • G56.20 Lesion of ulnar nerve, unspecified upper limb
        • G56.21 Lesion of ulnar nerve, right upper limb
        • G56.22 Lesion of ulnar nerve, left upper limb
        • G56.23 Lesion of ulnar nerve, bilateral upper limbs
        • G56.3 Lesion of radial nerve
        • G56.30 Lesion of radial nerve, unspecified upper limb
        • G56.31 Lesion of radial nerve, right upper limb
        • G56.32 Lesion of radial nerve, left upper limb
        • G56.33 Lesion of radial nerve, bilateral upper limbs
        • G56.4 Causalgia of upper limb
        • G56.40 Causalgia of unspecified upper limb
        • G56.41 Causalgia of right upper limb
        • G56.42 Causalgia of left upper limb
        • G56.43 Causalgia of bilateral upper limbs
        • G56.8 Other specified mononeuropathies of upper limb
        • G56.80 Other specified mononeuropathies of unspecified upper limb
        • G56.81 Other specified mononeuropathies of right upper limb
        • G56.82 Other specified mononeuropathies of left upper limb
        • G56.83 Other specified mononeuropathies of bilateral upper limbs
        • G56.9 Unspecified mononeuropathy of upper limb
        • G56.90 Unspecified mononeuropathy of unspecified upper limb
        • G56.91 Unspecified mononeuropathy of right upper limb
        • G56.92 Unspecified mononeuropathy of left upper limb
        • G56.93 Unspecified mononeuropathy of bilateral upper limbs

Instructional Notations

Type 1 Excludes

A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.

  • current traumatic nerve disorder - see nerve injury by body region

Clinical Terms

The following clinical terms provide additional context, helping users better understand the clinical background and common associations for each diagnosis listed in this section. Including related terms alongside ICD-10-CM codes supports coders, billers, and healthcare professionals in improving accuracy, enhancing documentation, and facilitating research or patient education.

Carpal Tunnel Syndrome

Entrapment of the MEDIAN NERVE in the carpal tunnel, which is formed by the flexor retinaculum and the CARPAL BONES. This syndrome may be associated with repetitive occupational trauma (CUMULATIVE TRAUMA DISORDERS); wrist injuries; AMYLOID NEUROPATHIES; rheumatoid arthritis (see ARTHRITIS, RHEUMATOID); ACROMEGALY; PREGNANCY; and other conditions. Symptoms include burning pain and paresthesias involving the ventral surface of the hand and fingers which may radiate proximally. Impairment of sensation in the distribution of the median nerve and thenar muscle atrophy may occur. (Joynt, Clinical Neurology, 1995, Ch51, p45)

Median Neuropathy

Disease involving the median nerve, from its origin at the BRACHIAL PLEXUS to its termination in the hand. Clinical features include weakness of wrist and finger flexion, forearm pronation, thenar abduction, and loss of sensation over the lateral palm, first three fingers, and radial half of the ring finger. Common sites of injury include the elbow, where the nerve passes through the two heads of the pronator teres muscle (pronator syndrome) and in the carpal tunnel (CARPAL TUNNEL SYNDROME).

Radial Neuropathy

Disease involving the RADIAL NERVE. Clinical features include weakness of elbow extension, elbow flexion, supination of the forearm, wrist and finger extension, and thumb abduction. Sensation may be impaired over regions of the dorsal forearm. Common sites of compression or traumatic injury include the AXILLA and radial groove of the HUMERUS.