Cubital Tunnel Syndrome

Ovid: 5-Minute Sports Medicine Consult, The

Cubital Tunnel Syndrome
Jeffrey Rosenberg
Thomas A. Phipps
  • Compression, traction, or irritation of the ulnar nerve as it passes through the cubital tunnel of the medial elbow
  • The cubital tunnel is bounded by the medial trochlea, the medial epicondylar groove, and the posterior portion of the ulnar collateral ligament and is roofed by the triangular arcuate ligament.
  • Primary complaints are medial elbow and forearm pain.
  • Additional complaints are paresthesias in the ring and little fingers.
  • Synonym(s): Ulnar tunnel syndrome
  • The elbow is the most common site of compression of the ulnar nerve.
  • Predominant gender: Male > Female (3–8:1)
  • The 2nd most common compressive neuropathy (after carpal tunnel syndrome)
  • Overhead throwing athletes are most at risk.
Risk Factors
  • Overhead throwing athletes
  • Repetitive upper extremity activities
  • Diabetes
  • Obesity
  • Peripheral neuropathies
General Prevention
Avoid prolonged pressure on the medial elbow.
Possible causes of the compression of the ulnar nerve as it passes the medial elbow include:
  • Subluxation of the ulnar nerve over the medial epicondyle
  • Enlarged medial head of the triceps muscle
  • Cubitus valgus
  • Ulnar collateral ligament instability/tears
  • Triangular arcuate ligament tears in baseball pitchers
  • Osteophytes
  • Ganglia or lipomas
  • Tumors
  • Repetitive elbow flexion and extension
  • Anconeus epitrochlearis: Anomalous muscle in 70% of population
Commonly Associated Conditions
  • Ulnar neuritis
  • Ulnar collateral ligament instability
  • Vague, aching pain in the region of the elbow, worsening with overhead activities
  • Paresthesias over the 4th and 5th digits
  • Numbness of the 4th and 5th digits
  • Weakness of interosseous muscles of the hand
  • Worsening grip and clumsiness
  • Snapping or popping sensation of medial elbow
  • Overhead throwing athletes will complain of loss of control of ball with activity.
Physical Exam
  • Pain with palpation of cubital tunnel of affected elbow
  • Positive Tinel sign: Tapping over the ulnar nerve at the elbow will cause a reproduction of symptoms (1).
  • Elbow flexion test: Placing the elbow in full flexion and the wrist in maximal extension will cause pain or paresthesias after 1 min (1).
  • Scratch test: Patient faces examiner with arms adducted, elbows flexed, and hands outstretched with wrists in a neutral position. Patient resists adduction/internal rotation to the forearms applied by the examiner. The examiner scratches or wipes fingertips over the cubital tunnel, and resistance to adduction/internal rotation is again applied. In a positive test, the patient has immediate and temporary loss of external resistance tone, which resolves within 5 sec (1).
  • Sensory changes in ulnar nerve distribution can be detected with Semmes-Weinstein monofilament testing and, in more advanced cases, with 2-point discrimination tests.
  • Asymmetric hypothenar atrophy, decreased pinch and grip strength, abducted little finger, or severe claw deformity of little finger only (Wartenberg sign)
  • Intrinsic muscle weakness and wasting (especially 1st dorsal interosseous muscle)
  • Patient will exhibit decreased sensation in the ulnar nerve distribution.
Diagnostic Tests & Interpretation
  • Complete medical history and physical exam
  • Nerve conduction velocity (NCV) to determine how fast neurologic signals travel down nerve to detect site of compression or constriction. Studies must be performed with elbow at 45 degrees of flexion to lessen chance of erroneous results (2).
  • Electromyogram (EMG) to evaluate nerve and muscle function
  • Radiograph of elbow to evaluate for bony changes or spurs
  • MRI of elbow to evaluate cubital tunnel for soft tissue masses and continuity of ulnar collateral ligament
  • Diagnostic US: Ratio of ulnar nerve cross-sectional area at maximal enlargement to cross-sectional area at unaffected site >2.8:1; ratio in control subjects 1.1:1 (3)
Pathological Findings
  • At decompression, specific sites of nerve compression usually can be found.
  • Inspect the arcade of Struthers, intermuscular septum, cubital tunnel, and Osborne fascia (between 2 heads of flexor carpi ulnaris).


Differential Diagnosis
  • Systemic: Diabetes, renal disease, multiple myeloma, amyloidosis, chronic alcoholism, malnutrition
  • Compression: Postoperative occupational or recreational activities requiring repetitive flexion and extension, supracondylar process, ligament of Struthers, medial head of triceps, ulnar nerve compression at Guyon canal
  • Medial epicondylitis
  • Ulnar collateral ligament injury
  • Cervical radiculopathy
  • Thoracic outlet syndrome
  • Carpel tunnel syndrome
354.2 Lesion of ulnar nerve

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