S54.8X9 Injury of other nerves at forearm level, unspecified arm

ICD-10-CM S54.8X9: Injury of other nerves at forearm level, unspecified arm

ICD-10-CM code S54.8X9 designates an injury of other nerves at the forearm level on an unspecified arm. This diagnosis concept captures nerve injuries in the forearm when the specific affected arm is not documented. The code is distinct from related variants that specify laterality or encounter type, and it does not inherently guarantee payer coverage. 5 3 4

Plain-language overview

Code S54.8X9 represents an injury of other nerves at the forearm level, unspecified arm. This diagnosis concept is used when a patient has a forearm nerve injury but the clinical documentation does not specify which arm is affected. 5

What this code represents

The S54.8X9 diagnosis code specifically denotes an injury of other nerves at the forearm level without identifying the right or left arm. It is categorized under the ICD-10-CM system for the 2026 version release. 5

Coding details

The S54.8X9 code lacks the laterality and encounter character found in related variants such as S54.8X2D for a left arm subsequent encounter or S54.8X1D for a right arm subsequent encounter. 3 4

The Centers for Medicare and Medicaid Services list specific S54.8X codes that include initial encounter, subsequent encounter, and sequela designations for right and left arm nerve injuries at the forearm level. 3 4

Documentation considerations

Clinical anatomy sources indicate that forearm nerve injuries can involve the radial, median, or musculocutaneous nerves, resulting in distinct motor or sensory impairments depending on the specific nerve affected. 1 2

Clinical context

Injury to the radial nerve in the brachial region impairs the muscles of the entire posterior compartment of the forearm, while musculocutaneous nerve injury causes weakness in elbow flexion and forearm supination. 1

Radial nerve injury may be caused by compression against a patient screen or arm board, resulting in paraesthesia along the posterior surface of the lower part of the arm and forearm. 2

What the sources add

The CMS sources provide billing and coding context by listing specific encounter types and laterality for S54.8X codes, whereas the PMC sources describe the anatomical and clinical impacts of upper limb nerve injuries. 3 4 1 2

Coverage and utilization context

The appearance of S54.8X codes in Medicare billing and coding articles for nerve blockade and nerve conduction studies establishes their administrative use, but does not imply that any specific code guarantees payer coverage. 3 4

Sources

1. Avoiding peripheral nerve injury in arterial interventions — pmc.ncbi.nlm.nih.gov; accessed 2026-07-25.
2. Clinical anatomy of the nerve supply to the upper limb — pmc.ncbi.nlm.nih.gov; accessed 2026-07-25.
3. Article - Billing and Coding: Nerve Blockade for Treatment of Chronic Pain and Neuropathy (A56034) — cms.gov; accessed 2026-07-25.
4. Article - Billing and Coding: Nerve Conduction Studies and Electromyography (A57123) — cms.gov; accessed 2026-07-25.
5. EVS Explore — evsexplore.semantics.cancer.gov; accessed 2026-07-25.