What is the condition called when a patient experiences tingling in the outer three fingers of the hand, specifically related to the ulnar nerve?

Ulnar Neuropathy

Tingling in the outer three fingers of the hand (ring finger, little finger, and ulnar aspect of the middle finger) is called ulnar neuropathy or ulnar nerve entrapment. 1, 2

Clinical Presentation

The ulnar nerve innervates the little finger and the ulnar (outer) half of the ring finger, producing characteristic sensory symptoms in this distribution when compressed or injured 3, 4:

• Numbness and tingling in the little finger and ulnar aspect of the ring finger are the hallmark sensory symptoms 3, 4
• Intrinsic hand muscle weakness may develop, particularly affecting grip strength and fine motor control 2, 3
• Muscle atrophy of the hand can occur in more advanced cases 2

Most Common Sites of Entrapment

Ulnar neuropathy at the elbow (cubital tunnel syndrome) is the second most common nerve entrapment after carpal tunnel syndrome and represents the most frequent location for ulnar nerve compression 1, 2, 5:

• The nerve can be entrapped under the humero-ulnar arcade (cubital tunnel) or at the retro-epicondylar groove 1
• Less commonly, compression occurs at the wrist (ulnar tunnel syndrome) or in the forearm 1, 4

Diagnostic Approach

Electrodiagnostic studies (nerve conduction studies and EMG) are moderately sensitive for diagnosis and can differentiate between demyelinating versus axonal injury 6, 1:

• The classic "sural sparing pattern" helps differentiate ulnar neuropathy from other conditions 7
• Reduced sensory nerve action potential amplitude indicates axonal degeneration 6

Ultrasound imaging provides superior localization compared to electrodiagnostic studies alone, with sensitivity of 77-79% and specificity of 94-98% for assessing nerve cross-sectional area and thickness 7, 6:

• Shear-wave elastography demonstrates 100% specificity and sensitivity for diagnosing ulnar neuropathy at the elbow 7, 6
• MRI with T2-weighted neurography is the reference standard, showing high signal intensity and nerve enlargement 7, 6

Initial Management

For mild to moderate cases, conservative management should be attempted first 5, 3:

• Provide specific information on avoiding prolonged elbow flexion beyond 90° and positions that compress the ulnar groove, as this is effective in improving subjective discomfort 8, 7, 5
• Apply foam or gel padding at the elbow to prevent further compression, but ensure padding is not too tight as this can paradoxically worsen symptoms 7
• Maintain neutral forearm position when arm is at the side, or use supinated/neutral position when arm is abducted on an armboard 7, 6
• Limit arm abduction to 90° in supine position 8, 7, 6

For pain management, use a stepwise approach 7, 6:

• Paracetamol (up to 4g/day) as first-line oral analgesic 7, 6
• Topical NSAIDs for localized pain with fewer systemic side effects 7, 6
• Oral NSAIDs at lowest effective dose for shortest duration if inadequate response 6

Range of motion and strengthening exercises with local heat application before exercise should be prescribed to maintain function 7, 6

When Conservative Treatment Fails

Corticosteroid injection showed no benefit versus placebo at three months' follow-up 5

Surgical intervention should be considered when conservative measures fail or when sensory/motor impairment progresses 5, 3:

• Simple decompression and decompression with transposition are equally effective for clinical and neurophysiological improvement (91 out of 131 improved with simple decompression versus 97 out of 130 with transposition) 5
• Simple decompression has fewer wound infections compared to transposition (RR 0.32,95% CI 0.12 to 0.85), making it the preferred surgical approach when both are equally effective 5
• Endoscopic versus open decompression showed no difference in clinical outcomes, though endoscopic surgery had higher hematoma risk 5

Important Clinical Pitfalls

Avoid these common errors 8, 7:

• Do not use padding that is too tight, as it creates a tourniquet effect and worsens compression 7
• Do not assume all ulnar neuropathy at the elbow is "cubital tunnel syndrome"—imaging can distinguish between cubital tunnel entrapment and retro-epicondylar groove injury, which may require different management 1
• Night splinting and nerve gliding exercises added to information provision did not result in further improvement beyond information alone 5

Regular follow-up is essential to monitor for progression or improvement of symptoms 7