Facial nerve disorders (G51) ICD-10-CM
The G51 code range covers facial nerve disorders with 12 ICD-10-CM diagnosis codes. 10 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Includes
This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
- disorders of 7th cranial nerve
Codes in the G51 Range 12 codes · 10 billable
- G51 Facial nerve disordersNon-billable
- G51.0 Bell's palsy
- G51.1 Geniculate ganglionitis
- G51.2 Melkersson's syndrome
- G51.3 Clonic hemifacial spasmNon-billable
- G51.31 Clonic hemifacial spasm, right
- G51.32 Clonic hemifacial spasm, left
- G51.33 Clonic hemifacial spasm, bilateral
- G51.39 Clonic hemifacial spasm, unspecified
- G51.4 Facial myokymia
- G51.8 Other disorders of facial nerve
- G51.9 Disorder of facial nerve, unspecified
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the G51 range.
Facial Hemiatrophy
A syndrome characterized by slowly progressive unilateral atrophy of facial subcutaneous fat, muscle tissue, skin, cartilage, and bone. The condition typically progresses over a period of 2-10 years and then stabilizes.
Facial Nerve Diseases
Diseases of the facial nerve or nuclei. Pontine disorders may affect the facial nuclei or nerve fascicle. The nerve may be involved intracranially, along its course through the petrous portion of the temporal bone, or along its extracranial course. Clinical manifestations include facial muscle weakness, loss of taste from the anterior tongue, hyperacusis, and decreased lacrimation.
Facial Neuralgia
Neuralgic syndromes which feature chronic or recurrent FACIAL PAIN as the primary manifestation of disease. Disorders of the trigeminal and facial nerves are frequently associated with these conditions.
Facial Pain
Pain in the facial region including orofacial pain and craniofacial pain. Associated conditions include local inflammatory and neoplastic disorders and neuralgic syndromes involving the trigeminal, facial, and glossopharyngeal nerves. Conditions which feature recurrent or persistent facial pain as the primary manifestation of disease are referred to as FACIAL PAIN SYNDROMES.
Hemifacial Spasm
Recurrent clonic contraction of facial muscles, restricted to one side. It may occur as a manifestation of compressive lesions involving the seventh cranial nerve (FACIAL NERVE DISEASES), during recovery from BELL PALSY, or in association with other disorders. (From Adams et al., Principles of Neurology, 6th ed, p1378)
Isaacs Syndrome
A rare neuromuscular disorder with onset usually in late childhood or early adulthood, characterized by intermittent or continuous widespread involuntary muscle contractions; FASCICULATION; hyporeflexia; MUSCLE CRAMP; MUSCLE WEAKNESS; HYPERHIDROSIS; TACHYCARDIA; and MYOKYMIA. Involvement of pharyngeal or laryngeal muscles may interfere with speech and breathing. The continuous motor activity persists during sleep and general anesthesia (distinguishing this condition from STIFF-PERSON SYNDROME). Familial and acquired (primarily autoimmune) forms have been reported. (From Ann NY Acad Sci 1998 May 13;841:482-496; Adams et al., Principles of Neurology, 6th ed, p1491)
Myokymia
Successive and rapid contractions of motor units associated with chronic nerve injury. The discharges arise from the peripheral aspects of regenerating nerves, and clinically impart a nearly continuous undulation of the body surface overlying the muscle. (Adams et al., Principles of Neurology, 6th ed, p1491)
Trochlear Nerve Diseases
Diseases of the fourth cranial (trochlear) nerve or its nucleus in the midbrain. The nerve crosses as it exits the midbrain dorsally and may be injured along its course through the intracranial space, cavernous sinus, superior orbital fissure, or orbit. Clinical manifestations include weakness of the superior oblique muscle which causes vertical DIPLOPIA that is maximal when the affected eye is adducted and directed inferiorly. Head tilt may be seen as a compensatory mechanism for diplopia and rotation of the visual axis. Common etiologies include CRANIOCEREBRAL TRAUMA and INFRATENTORIAL NEOPLASMS.
About the G51 Code Range
The ICD-10 code section G51 covers disorders affecting the facial nerve, which controls muscles responsible for facial expression. This set of codes is used to classify various specific conditions that involve facial nerve dysfunction or irritation.
Within this category, G51.0 is notably used for Bell’s palsy, which includes sudden weakness or paralysis of facial muscles and is often referred to by common terms such as "facial palsy," "peripheral facial palsy," or "supranuclear facial nerve paralysis." Other specific codes address conditions like geniculate ganglionitis (G51.1), Melkersson’s syndrome (G51.2) known also as "Cheilitis granulomatosa," and various types of clonic hemifacial spasms (G51.3x) distinguished by side of the face involved. Additionally, G51.4 represents facial myokymia, characterized by involuntary muscle twitching. The code G51.8 covers other less common facial nerve disorders such as facial neuralgia and hereditary geniospasm, while G51.9 is used for unspecified facial nerve disorders. These codes help healthcare providers and coders precisely document facial nerve issues for diagnosis, treatment, and reporting purposes.
Questions About This Page
How many billable codes are in the G51 range?
Of the 12 codes in this range, 10 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the G51 range classify?
The range classifies facial nerve disorders. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
