Neck & Arm Neuropathies

Neck and arm neuropathies encompass various conditions affecting the nerves that supply the upper extremities, including cervical radiculopathies and peripheral nerve entrapments.

What is involved?

Multiple nerves and nerve roots of the upper extremity:

• Cervical nerve roots (C5-T1)
• Brachial plexus
• Peripheral nerves (Median, Ulnar, Radial, Musculocutaneous)

Location

• Cervical Spine: nerve root compression at the neural foramen
• Brachial Plexus: from neck to axilla
• Arm and Forearm: various entrapment sites along peripheral nerves

Common symptoms

Symptoms vary by location and nerve involved:

Cervical Radiculopathy

• Neck pain radiating to arm/shoulder
• Dermatomal numbness and tingling
• Weakness in specific muscle groups
• Pain often worse with neck movement

Brachial Plexopathy

• Shoulder and arm weakness
• Diffuse arm numbness
• May follow trauma, surgery, or be idiopathic (Parsonage-Turner)

Peripheral Nerve Entrapments

• Carpal Tunnel: thumb, index, middle finger numbness; nocturnal symptoms
• Ulnar Neuropathy: fourth and fifth finger numbness; hand weakness
• Radial Neuropathy: wrist drop; dorsal hand numbness

Onset

• Radiculopathy: can be sudden (disc herniation) or gradual (spondylosis)
• Brachial Plexopathy: sudden onset in Parsonage-Turner; gradual in tumors
• Entrapments: usually gradual over weeks to months

Risk factors

• Cervical spondylosis (degenerative disc disease)
• Disc herniation
• Trauma
• Repetitive activities
• Diabetes mellitus
• Occupational factors
• Previous surgery (especially for brachial plexopathy)
• Viral illness (can precede Parsonage-Turner syndrome)

Exam

General Assessment

• Neck range of motion
• Spurling’s test (radiculopathy)
• Upper extremity strength testing by myotome
• Sensory examination by dermatome
• Deep tendon reflexes (biceps C5-6, triceps C7, brachioradialis C6)

Specific Tests

• Tinel’s sign at various entrapment sites
• Phalen’s test (carpal tunnel)
• Elbow flexion test (ulnar neuropathy)

Key Muscle Groups by Root

• C5: Deltoid, Biceps
• C6: Biceps, Wrist extensors, Brachioradialis
• C7: Triceps, Wrist flexors, Finger extensors
• C8: Finger flexors, Hand intrinsics
• T1: Hand intrinsics

EMG

EMG is essential for localization and determining severity.

For Cervical Radiculopathy

• Paraspinal muscle involvement helps confirm root level
• Look for denervation in muscles from same root but different peripheral nerves
• Sensory nerve studies normal (lesion proximal to dorsal root ganglion)

For Brachial Plexopathy

• Abnormalities span multiple nerve territories
• Sensory potentials affected (lesion distal to DRG)
• Localize to upper, middle, or lower trunk

For Peripheral Entrapments

• Focal slowing or conduction block at entrapment site
• Denervation limited to muscles distal to lesion
• Compare side-to-side

Findings by Condition

Condition	Motor NCS	Sensory NCS	Needle EMG
Radiculopathy	Usually normal	Normal	Denervation in myotome + paraspinals
Plexopathy	Abnormal	Abnormal	Denervation across trunk distribution
Entrapment	Focal slowing	May be abnormal	Denervation distal to lesion

Recommendations

Cervical Radiculopathy

• Conservative treatment initially (physical therapy, NSAIDs)
• Cervical collar for acute pain
• Epidural steroid injections
• Surgery for severe weakness or failed conservative treatment

Brachial Plexopathy

• Treat underlying cause
• Physical therapy
• Pain management
• Parsonage-Turner: supportive care, usually recovers over 1-3 years

Peripheral Entrapments

• Activity modification
• Splinting
• Injections
• Surgical release for severe or progressive cases

What else could it be?

• Motor Neuron Disease (ALS): if weakness without sensory loss in multiple regions
• Cervical Myelopathy: if upper motor neuron signs present
• Thoracic Outlet Syndrome: vascular and neurogenic symptoms
• Peripheral Neuropathy: if bilateral and symmetric
• Myopathy: proximal weakness, elevated CK
• Rotator Cuff Pathology: shoulder pain/weakness without neurological findings