What is Cubital Tunnel Syndrome (Ulnar Nerve Entrapment)?

Topographical Anatomy of the Cubital Tunnel

The ulnar nerve traverses the posterior aspect of the medial epicondyle through the fibroaponeurotic cubital tunnel. Prolonged or repetitive elbow flexion dramatically increases intraneural pressure, causing microvascular ischemia, friction elongation, and neural tethering.

Hallmark Clinical Presentation

• Paresthesias and hypoesthesia isolated to the small finger and ulnar half of the ring finger
• Symptom exacerbation during sustained elbow flexion (holding mobile phones, sleeping postures)
• Weakness of intrinsic hand muscles, diminished pinch grip, and difficulty opening jars
• First dorsal interosseous muscle atrophy and severe 'claw hand' posture in end stages

Diagnostic Confirmation and Management

Positive Tinel's sign at the medial epicondyle and elbow flexion-compression testing warrant electrodiagnostic confirmation (EMG/NCS). Surgical decompression (in situ release or anterior transposition) prevents permanent motor denervation.

Frequently Asked Questions

How does cubital tunnel differ from carpal tunnel syndrome?

Carpal tunnel affects the median nerve at the wrist (thumb/index/middle fingers), while cubital tunnel involves the ulnar nerve at the elbow (ring and little fingers).

What is anterior transposition of the ulnar nerve?

When the nerve subluxates over the medial epicondyle during flexion, it is surgically mobilized anteriorly into subcutaneous or submuscular tissue to relieve tension.