Case presentation

A 68-year-old man presented to the Department of Physical Medicine and Rehabilitation at our university hospital with a 3-month history of tingling pain involving the medial aspect of the right forearm and hand. He denied any history of trauma or systemic diseases. Pain intensity was rated as 5 on the numeric rating scale (NRS), a self-reported measure in which 0 represents no pain and 10 denotes the worst pain imaginable. Neurological examination revealed a positive Spurling test result on the right side (Fig. 1). Sensory assessment revealed hypoalgesia over the right fifth finger and medial aspect of the right hand. Motor testing demonstrated reduced strength during abduction of the right fifth finger. Deep tendon reflexes, including biceps and triceps jerks, were bilaterally normoactive. The Hoffmann sign was absent on both sides, and the Roos and Adson tests were negative bilaterally.

Differential diagnosis

The following potential diagnoses were considered.

1. Cervical radiculopathy due to foraminal stenosis or herniated disc

In cases of C8 radiculopathy resulting from cervical foraminal stenosis or disc herniation, neuropathic pain typically involves the medial aspect of the forearm and hand. The presence of a positive Spurling sign suggests possible C8 radiculopathy related to foraminal stenosis or a herniated cervical disc. Concurrent sensory and motor deficits further supported this diagnosis.

2. Cubital tunnel syndrome

Cubital tunnel syndrome is a common musculoskeletal disorder caused by compression or irritation of the ulnar nerve at the elbow. This entrapment leads to numbness, tingling, and pain along the medial forearm, hand, and fourth and fifth digits. Considering the patient’s hypoalgesia over the right fifth finger and medial hand, along with tingling pain in the medial aspect of the right forearm and hand, this condition was considered a possible diagnosis.

3. Guyon’s canal syndrome

Guyon’s canal syndrome refers to ulnar nerve entrapment at the level of the wrist, specifically within Guyon’s canal, a fibro-osseous tunnel situated between the pisiform and the hook of the hamate. This condition typically arises from compression of the ulnar nerve as it traverses the canal, resulting in numbness and tingling in the fourth and fifth digits as well as weakness of the intrinsic hand muscles. Unlike C8 radiculopathy or cubital tunnel syndrome, Guyon’s canal syndrome does not cause sensory changes in the forearm because the site of compression is distal to the nerve branches that supply this region. Therefore, this syndrome was considered a less likely diagnosis than the two aforementioned disorders.

4. Thoracic outlet syndrome

Thoracic outlet syndrome (TOS) can be classified as neurogenic, venous, or arterial, depending on the structure compressed within the thoracic outlet. Neurogenic TOS, the most common form, typically involves compression of the lower trunk of the brachial plexus and may present with neuropathic pain along the medial aspect of the upper extremity, often accompanied by weakness of the intrinsic hand muscles. Although the patient’s presentation was suggestive of neurogenic TOS, negative Roos and Adson test results reduced the likelihood of this diagnosis.

Diagnosis

T2-weighted axial cervical magnetic resonance imaging (MRI) revealed foraminal stenosis at the right C7–T1 level (Fig. 2A). Electrodiagnostic studies, including nerve conduction studies (NCS) and needle electromyography (EMG), were performed. The NCS results for the right ulnar and median nerves were within normal limits. The absence of ulnar nerve abnormalities effectively excluded both cubital tunnel syndrome and Guyon’s canal syndrome. Needle EMG revealed active denervation potentials in the right abductor digiti minimi, first dorsal interosseous, and paraspinal muscles, findings consistent with right C8 nerve root involvement. These results confirmed the diagnosis of right C8 radiculopathy.

Treatment and prognosis

Right C8 selective nerve root injection was performed using 10 mg (2 mL) of dexamethasone combined with 0.25 mL of 1% lidocaine (Fig. 2B). Two weeks after the procedure, the patient’s pain score decreased from 5 to 1 on the NRS. Pain remained stable at an NRS score of 1 during follow-up evaluations at 1, 2, and 3 months post-procedure.

Discussion

This case highlights the importance of an integrated clinical, imaging, and electrodiagnostic approach for evaluating patients with neuropathic pain involving the medial aspect of the forearm and hand. The initial presentation prompted the consideration of multiple differential diagnoses, including cervical radiculopathy, cubital tunnel syndrome, Guyon’s canal syndrome, and TOS, each of which may present with sensory and motor deficits within the ulnar nerve distribution [1].

Among these possibilities, C8 cervical radiculopathy was most strongly supported by the presence of a positive Spurling sign. The Spurling maneuver is a well-established provocative test used to identify cervical nerve root compression. During this test, axial compression is applied to the patient’s head while extending and rotating it toward the symptomatic side [2]. A positive result, defined as the reproduction of radicular pain, indicates nerve root irritation or compression. Although the sensitivity of the Spurling sign is relatively modest (approximately 30%–50%), its specificity is high, typically between 90% and 95%, making it a reliable indicator for confirming cervical radiculopathy when positive [2]. MRI findings of foraminal stenosis at the C7 to T1 level, corresponding to the exit of the C8 nerve root, provided anatomical evidence supporting these clinical findings. Consistent with this, needle EMG demonstrated active denervation in muscles innervated by the C8 root, including the abductor digiti minimi, first dorsal interosseous, and paraspinal muscles, thereby reinforcing the diagnosis.

The patient experienced substantial symptom improvement following a C8 selective nerve root corticosteroid injection, further corroborating the diagnosis of C8 radiculopathy. Previous studies have demonstrated that corticosteroid injections are effective in relieving radicular pain associated with cervical foraminal stenosis by reducing inflammation and neural irritation [3–5]. The therapeutic efficacy of corticosteroids is primarily attributed to their anti-inflammatory effects, which reduce perineural edema, inhibit the production of proinflammatory cytokines, and stabilize neuronal membranes, thereby alleviating nerve root irritation and neuropathic pain [6,7].

In conclusion, this case highlights the critical importance of differentiating cervical radiculopathy from peripheral nerve entrapment syndrome when evaluating sensory and motor symptoms in the ulnar nerve distribution. Comprehensive neurological examination, appropriate imaging, and electrodiagnostic testing are essential to accurately localize the lesion and guide effective treatment selection.

Educational pearls

1. Cervical radiculopathy can mimic peripheral nerve entrapment syndromes

C8 radiculopathy may present with clinical features resembling cubital tunnel syndrome or Guyon’s canal syndrome, including numbness, tingling, and weakness within the ulnar nerve distribution. Meticulous physical examination complemented by imaging and electrodiagnostic studies is crucial to accurately differentiate these conditions.

2. Spurling sign is a strong clinical indicator of cervical radiculopathy due to foraminal stenosis or herniated disc

Although its sensitivity is limited, a positive Spurling sign demonstrates high specificity and serves as a reliable diagnostic tool for identifying cervical nerve root compression.

3. Corticosteroid injections can be effective in the treatment of cervical radiculopathy

Through the reduction of perineural inflammation and edema, corticosteroids alleviate nerve root irritation secondary to foraminal stenosis or disc herniation, thereby mitigating neuropathic pain and improving clinical outcomes.

Article information

Ethics statement

This study was approved by the Institutional Review Board (IRB) of Yeungnam University Hospital (IRB No. 2025-10-024). Written informed consent was obtained from the patient for publication of this report.

Conflicts of interest

Min Cheol Chang has been a Deputy Editor of the Journal of Yeungnam Medical Science since 2025. He was not involved in the review process of this manuscript. There are no other conflicts of interest to declare.

Funding

None.

Author Contributions

Conceptualization, Data curation, Investigation, Methodology Validation, Visualization: JS, MCC; Resources, Supervision: MCC; Writing-original draft: JS, MCC; Writing-review & editing: JS, MCC.

Fig. 1.

Spurling test maneuver. The Spurling test is performed with the patient’s neck extended and rotated toward the symptomatic side, while axial compression is applied. A positive response reproduces radicular pain, indicating cervical nerve root compression.

Fig. 2.

(A) Cervical magnetic resonance imaging (MRI) findings. T2-weighted axial cervical MRI demonstrates right foraminal stenosis (arrow) at the C7 to T1 level. corresponding to the exit of the C8 nerve root. (B) C8 selective nerve root injection procedure. Fluoroscopic image showing needle placement adjacent to the right C8 nerve root. The patient received an injection of 10 mg (2 mL) of dexamethasone mixed with 0.25 mL of 1% lidocaine.

References

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• 2. Lin LH, Lin TY, Chang KV, Tzang CC, Wu WT, Özçakar L, et al. Diagnostic performance of Spurling’s test for the assessment subacute and chronic cervical radiculopathy: a systematic review and meta-analysis. Am J Phys Med Rehabil 2025;104:717–23.ArticlePubMed
• 3. Kim MS, Lee DG, Chang MC. Outcome of transforaminal epidural steroid injection according to severity of cervical foraminal stenosis. World Neurosurg 2018;110:e398–403.ArticlePubMed
• 4. Wang MX, Kim JK, Chang MC. Deep learning algorithm trained on cervical magnetic resonance imaging to predict outcomes of transforaminal epidural steroid injection for radicular pain from cervical foraminal stenosis. J Pain Res 2023;16:2587–94.ArticlePubMedPMCPDF
• 5. Wang MX, Kim JK, Kim CR, Chang MC. Deep learning algorithm trained on oblique cervical radiographs to predict outcomes of transforaminal epidural steroid injection for pain from cervical foraminal stenosis. Pain Ther 2024;13:173–83.ArticlePubMedPMCPDF
• 6. Chang MC. The blind spot and challenges in pain management. J Yeungnam Med Sci 2022;39:179–80.ArticlePubMedPMCPDF
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References

Citations

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• A 70-year-old man presenting with weakness in the left hand and tingling pain in the ulnar aspect of the left hand
  Byungkwan Park, Ji Hwan Kim, Gyu-Sik Choi, Min Cheol Chang
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