S44.20XA Injury of radial nerve at upper arm level, unspecified arm, initial encounter

ICD-10-CM Code S44.20XA: Injury of radial nerve at upper arm level, unspecified arm, initial encounter

ICD-10-CM code S44.20XA designates an initial encounter for an injury of the radial nerve at the upper arm level on an unspecified arm. The terminology record classifies this concept as an injury or poisoning. Clinical literature notes that proximal radial nerve lesions in the upper arm often result from trauma and can lead to functional impairments like wrist drop. 1 2

Plain-language overview

Code S44.20XA describes an injury to the radial nerve at the upper arm level during an initial encounter, without specifying which arm is affected, serving as an active diagnostic concept. 1

What this code represents

The terminology record assigns S44.20XA a semantic type of Injury or Poisoning and nests it under the parent concept S44.20 for an unspecified arm radial nerve injury at the upper arm level. 1

Clinical context

Proximal radial nerve lesions involving the upper arm often result from trauma, such as shoulder dislocation or direct injury, and can produce motor weakness or sensory deficits. 2

Radial nerve injury can lead to wrist drop, a disabling condition resulting in the loss of wrist, finger, and thumb extension due to denervation of the extensor musculature. 2

Documentation considerations

Clinical evaluation of radial nerve injuries involves focused neurologic examinations, electrodiagnostic studies, and imaging to localize the lesion and determine injury severity based on anatomical level. 2

Coverage and utilization context

Electrodiagnostic assessments may be considered medically necessary for traumatic nerve injuries when a definitive diagnosis cannot be made by physical exam and imaging studies alone. 4

What the sources add

While the terminology record defines the code's hierarchical structure and encounter type, clinical literature provides operational context regarding the trauma mechanisms and functional deficits associated with upper arm radial nerve injuries. 1 2

Sources

1. ICD-10-CM S44.20XA terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Bookshelf — ncbi.nlm.nih.gov; accessed 2026-07-27.
3. Article - Billing and Coding: Continuous Peripheral Nerve Blocks (CPNB) (A56607) — cms.gov; accessed 2026-07-27.
4. Electromyography and Nerve Conduction Studies — capbluecross.com; accessed 2026-07-27.
5. Codigo. The #1 Billing Agency for Medical Practices — codigo.care; accessed 2026-07-27.