Can a C4/C5 disc extrusion on the right side causing spinal cord edema and neuroforaminal narrowing result in right-sided finger drop as the only presentation?

Can C4/C5 Disc Extrusion with Spinal Cord Edema Present as Isolated Right-Sided Finger Drop?

No, isolated finger drop alone is highly unlikely to be the sole presentation of a C4/C5 disc extrusion causing spinal cord edema and neuroforaminal narrowing—this clinical picture demands a thorough search for additional myelopathic or radicular signs that are almost certainly present but may be subtle.

Understanding the Anatomical Mismatch

The clinical presentation described represents a significant anatomical and pathophysiological disconnect:

Spinal Cord Edema at C4/C5 Should Produce Myelopathy

• Spinal cord edema at C4/C5 typically manifests with bilateral hand weakness, gait disturbance, hyperreflexia, and sensory changes below the level of compression 1.
• The illustrative case from World Neurosurgery demonstrates that C4/C5 level cord compression presents with bilateral hand numbness and weakness, burning dysesthesias in forearms, and involvement of multiple muscle groups including biceps, triceps, wrist extensors, and finger flexors bilaterally—not isolated unilateral finger drop 1.
• Patients with cervical spinal cord injury at this level characteristically show hand dysfunction affecting both fine motor control and grip strength, often with lower extremity involvement 1.

C4/C5 Radiculopathy Does Not Cause Finger Drop

• The C5 nerve root (affected by C4/C5 pathology) primarily innervates the deltoid and biceps muscles, not finger extensors 2.
• Deltoid paralysis and shoulder abduction weakness are the hallmark of C5 radiculopathy, which can occur from C4/C5 disc herniation or foraminal stenosis 2.
• Finger drop (wrist and finger extension weakness) is classically associated with C6 or C7 radiculopathy, not C4/C5 pathology 1.

What You Should Actually Find on Examination

Expected Myelopathic Signs from Cord Edema

• Bilateral hand clumsiness and weakness (not just finger drop) 1
• Hyperreflexia in upper and lower extremities 3
• Positive Hoffmann sign and ankle clonus 3
• Gait disturbance or lower extremity weakness 1, 4
• Sensory level or patchy sensory changes 1
• Possible bladder dysfunction in severe cases 3

Expected Radicular Signs from C4/C5 Foraminal Narrowing

• Deltoid weakness (shoulder abduction) 2
• Biceps weakness 1, 2
• Pain radiating to the shoulder and lateral arm 1
• Diminished biceps reflex 2

Critical Clinical Pitfalls

Do Not Miss the Myelopathy

The presence of spinal cord edema on imaging is a red flag that demands identification of myelopathic signs 1. The case series from World Neurosurgery explicitly warns that patients with cord signal change can present with subtle findings initially but harbor significant myelopathy 1.

Consider Alternative Diagnoses for Isolated Finger Drop

If truly isolated right-sided finger drop is present without other findings:

• C6 or C7 radiculopathy from a different level (C5/C6 or C6/C7 disc herniation) 1
• Posterior interosseous nerve compression (radial nerve branch)
• C8 radiculopathy affecting intrinsic hand muscles
• Peripheral nerve pathology unrelated to the cervical spine

Beware of Progressive Neurological Deterioration

Cervical disc herniation with cord compression can cause rapid neurological deterioration, including progressive quadriparesis 4, 3. The case of cervical intradural disc herniation demonstrated that progressive weakness can develop over hours to days, starting with subtle symptoms 3.

Recommended Clinical Approach

Perform a Comprehensive Neurological Examination

• Test all upper extremity myotomes systematically: deltoid (C5), biceps (C5-C6), wrist extensors (C6), triceps (C7), finger flexors (C7-C8), and intrinsic hand muscles (C8-T1) 1, 2
• Assess reflexes: biceps, brachioradialis, triceps, and pathological reflexes (Hoffmann, Babinski) 3
• Evaluate gait and lower extremity strength and reflexes 1, 4
• Test sensory function in dermatomal distribution and for sensory level 1
• Assess hand dexterity and fine motor control (button test, coin test) 1

Correlate Imaging with Clinical Findings

MRI findings of cord edema at C4/C5 should correlate with clinical myelopathy—if they don't, either the examination is incomplete or the imaging findings are incidental 1. The ACR Appropriateness Criteria note that MRI has high rates of false-positive findings in asymptomatic individuals, and correlation with clinical examination is essential 1.

Surgical Considerations if Myelopathy is Confirmed

If true myelopathy with cord edema is present, urgent surgical decompression should be considered 4, 3. However, the World Neurosurgery case series provides a cautionary note: early surgery in patients with spinal cord injury without fracture-dislocation may not always improve outcomes and can potentially worsen neurological function 1.

Bottom Line

Isolated right-sided finger drop is not consistent with C4/C5 disc extrusion causing spinal cord edema and neuroforaminal narrowing 1, 2. Re-examine the patient meticulously for bilateral hand weakness, hyperreflexia, gait abnormalities, and other myelopathic signs that are almost certainly present 1, 3. If truly isolated finger drop exists, consider alternative diagnoses including pathology at C5/C6 or C6/C7 levels, or peripheral nerve involvement 1, 2.