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Cubital Tunnel Syndrome

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Other Names

  • Sulcus Ulnaris Syndrome
  • Retrocondylar Groove Syndrome



  • First described by Magee and Phalen in 1949[1]


  • Second most common entrapment neuropathy of upper extremity behind Carpal Tunnel Syndrome[2]
    • This is also the most common location for compression of the ulnar nerve
    • Incidence is 1/13 that of CTS[3]
  • Incidence 24.7 per 100,000 (need citation)
  • Male > Female[4]
  • Bilateral 18.6-38.8% of the time[5]


  • General
    • Marked by both sensory and motor deficiencies or dysesthesias
  • Can be differentiated into[6]
    • Primary or idiopathic
      • No morphological abnormalities, especially no bony changes of the elbow joint or space occupying lesions
    • Secondary
      • Deformation or other processes of the elbow joint


  • Entrapment occurs at many potential places[7]
    • Most common
      • Cubital tunnel (most common)
      • Deep flexor pronator aponeurosis
      • Arcade of Struthers
      • Osborns ligament
    • Less common
      • Medial intermuscular septum
      • Medial epicondyle
      • Hypertrophy of the medial head of the Triceps Brachii
      • Fascial bands within FCU
      • Accessory anconeus epitrochlearis muscle (3-23% of population)[8]
      • Aponeurosis of FDS proximal edge


  • Ulnar Nerve
    • C8, T1 nerve roots
    • Enters ulnar sulcus 3.5 cm proximal to medial epicondyle
    • Courses posterior to medial epicondyle, posterior to olecranon before entering cubital tunnel
  • Cubital Tunnel
  • Distal to cubital tunnel, courses deep into the forearm between the ulnar and humeral heads of the FCU
  • Note Medial Antebrachial Cutaneous Nerve is very proximal to cubital tunnel

Associated Conditions

Risk Factors

  • Repetitive work[9]
  • Obesity

Differential Diagnosis

Clinical Features


  • Diagnosis can often be made clinically
  • Onset is usually acute, or subacute as opposed to chronic and insidious
  • Parasthesias in ulnar nerve distribution
  • Pain is not a common or dominant feature but will report vague discomfort of medial elbow, forearm
  • Difficulty with certain activities like opening doors, jars, bottles
  • Rapidly fatigues with repetitive activities
  • Symptoms worse at night, with flexion

Physical: Physical Exam Elbow

  • Weakness, atrophy of intrinsic muscles of hand, especially 4th and 5th digit
  • Web space atrophy
  • Clawing of 4th, 5th digits
  • May see subluxing ulnar nerve at elbow with flexion-extension

Special Tests



  • Standard Radiographs Elbow
    • Useful screening tool
    • Unlikely to show any pathology in the setting of cubital tunnel syndrome
    • Can see osseus spurring in chronic patients


  • Findings[10]
    • Ulnar nerve thickening
    • Ulnar nerve T2 hyperintensity
    • Edema-like signal changes


  • Findings
    • Nerve appears hypoechoic
    • Ulnar nerve thickening > 9 mm[11]
    • Edematous changes


  • Useful to confirm diagnosis, especially pre-operatively and to exclude other diagnosis
  • Can see decrease in absolute conduction velocity to less than 50 m/s
  • Relative drop in conduction velocity of 10 m/s or more across a segment (usually the cubital tunnel)


McGowan classification of ulnar nerve dysfunction

  • Grade I: Sensory neuropathy only
  • Grade II: Sensory and motor neuropathy, without muscle atrophy
  • Grade III: Sensory and motor neuropathy, muscle atrophy present



  • Initial management is conservative almost universally
  • Activiity modification[12]
    • Avoid certain positions particularly elbow flexion, such as when talking on the telephone
    • Positions in which the medial elbow is resting on a hard surface, such as elbows on arm rests when working on a computer
  • Nighttime Elbow Flexion Block Splint
    • Night bracing in 45° extension with forearm in neutral rotation
  • Physical Therapy
    • Specifically, nerve glide exercises[13]


  • Indications
    • When conservative therapy fails
  • Technique
    • In situ decompression
    • Medical Epicondylectomy
    • Endoscopic Cubital Tunnel Release
    • Anterior Transposition

Rehab and Return to Play


  • Needs to be updated

Return to Play

  • Variable
  • Nonsurgical cases can return to play when symptoms resolve

Complications and Prognosis


  • Conservative management
    • Svernlov et al: 89.5% of patients demonstrated improvement in their symptoms with conservative management at the 3-month follow-up[14]


See Also


  1. Magee RB, Phalen GS. Tardy ulnar palsy. Am J Surg 1949;78:470–4
  2. Bozentka DJ. Cubital tunnel syndrome pathophysiology. Clin Orthop Relat Res 1998;351:90 –94
  3. Mondelli M, Giannini F, Ballerini M. et al . Incidence of ulnar neuropathy at the elbow in the province of Siena (Italy). J Neurol Sci. 2005; 15 5-10
  4. Assmus H, Antoniadis G,. Hrsg Nervenkompressionssyndrome.. Heidelberg: Steinkopff/Springer; 2008
  5. Artico M, Pastore FS, Nucci F. et al . 290 surgical procedures for ulnar nerve entrapment at the elbow: physiopathology, clinical experience and results. Acta Neurochir. 2000; 142 303-308
  6. Sunderland S. Nerves and nerve injuries.. Edinburgh, London, New York: Churchill Livingstone; 1978
  7. Ochiai N, Honmo J, Tsunjino A, Nisiura Y. Electrodiagnosis in entrapment neuropathy by the arcade of struthers. Clin Orthop Relat Res 2001;378:129 –135.
  8. Chan RC, Paine KWE, Varughese G. Ulnar neuropathy at the elbow: comparison of simple decompression and anterior transposition. Neurosurgery. 1980; 7 545-550
  9. Descatha A, Leclerc A, Chastang JF. et al. Study Group on RepetitiveWork Incidence of ulnar nerve entrapment at the elbow in repetitive work. Scand JWork Environ Health. 2004; 30 234-240
  10. https://radiopaedia.org/articles/cubital-tunnel-syndrome
  11. Choi SJ, Ahn JH, Ryu DS, Kang CH, Jung SM, Park MS, Shin DR. Ultrasonography for nerve compression syndromes of the upper extremity. (2015) Ultrasonography (Seoul, Korea). 34 (4): 275-91. doi:10.14366/usg.14060 - Pubmed
  12. Kroonen, Leo T. "Cubital tunnel syndrome." Orthopedic Clinics 43.4 (2012): 475-486.
  13. Bryon PM. Upper extremity nerve gliding: programs used at the Philadelphia Hand Center. In: Hunter JM, Mackin EJ, Callahand AD, editors. Rehabilitation of the hand: surgery and therapy. 4th edition. St Louis (MO): Mosby; 1995. p. 951–6.
  14. Svernlov B, Larsson M, Rehn K, et al. Conservative treatment of the cubital tunnel syndrome. J Hand Surg Br 2009;34:201–7.
Created by:
John Kiel on 4 July 2019 07:21:35
Last edited:
27 April 2023 10:37:00