II. Epidemiology

  1. Ulnar Neuropathy is the second most common arm compression Neuropathy
    1. However, much less common than Median Nerve compression
    2. Ulnar Neuropathy at the Elbow (Cubital Tunnel) is most common Ulnar Nerve injury site
  2. Incidence
    1. Peaks in men over age 35 years

III. Anatomy: Ulnar Nerve Course

  1. Spine
    1. C8 and T1 nerve roots
    2. Injury: Cervical Disc Herniation
  2. Axilla
    1. Brachial Plexus (medial aspect)
    2. Injury: Thoracic Outlet Syndrome
  3. Elbow
    1. Ulnar Groove at medial epicondyle
    2. Injury: Ulnar Neuropathy at the Elbow (Cubital Tunnel)
  4. Wrist
    1. Guyon canal (medial wrist)
      1. Medial border: Pisiform Bone
      2. Lateral border: Hamate Bone
      3. Anterior border: Flexor carpi ulnaris tendon, pisohamate ligament
      4. Posterior border: Transverse carpal ligament
    2. Injury: Ulnar Tunnel

IV. Causes: Ulnar Nerve compression

  1. Soft tissue tumors
  2. Ganglion Cyst
  3. Constricting bands or muscles
  4. Ulnar artery thrombosis
  5. Jackhammer or sledgehammer use
  6. Compression against handlebar in bicyclists

V. Risk Factors

  1. Prolonged and repetitive wrist extension
  2. Road Bicycling (Cyclist's Palsy, Handlebar Neuropathy)
  3. Karate
  4. Baseball (e.g. catcher)

VI. Symptoms: Distal Ulnar NerveNeuropathy

  1. General
    1. Wrist discomfort
  2. Sensory deficit in the ulnar 1.5 fingers on palmar surface (4th and 5th fingers)
    1. Does not affect Forearm or finger dorsum
  3. Motor Neuropathy is uncommon since the motor aspect of the nerve is deeper at the wrist
    1. Grip strength weakness may be present in chronic cases

VII. Signs

  1. Tinel sign (tap) over Guyon Canal
    1. Paresthesias into the 4th and 5th fingers
  2. Phalen Sign (maximal passive wrist flexion for >1 minute)
    1. Paresthesias into the 4th and 5th fingers

VIII. Differential Diagnosis

  1. See Wrist Pain
  2. Carpal Tunnel Syndrome
    1. Neuropathy is in Median Nerve distribution
  3. Ulnar Neuropathy at the Elbow (Cubital Tunnel)
    1. Affects ulnar innervation over Forearm
    2. Affects dorsal 1.5 fingers in ulnar distribution
  4. Thoracic Outlet Syndrome (or Brachial Plexopathy)
    1. Upper arm pain or weakness
  5. Cervical Radiculopathy (C7, C8, T1)
    1. Double crush injury may also occur (cervical root and Ulnar Nerve injury)
    2. Especially consider when bilateral symptoms are present

IX. Imaging

  1. Wrist XRay (first line)
    1. See Wrist Pain
    2. Evaluate for Fracture or dislocation
  2. Electrodiagnostics (second line)
    1. Nerve conduction velocities
      1. Acute entrapment Neuropathy
    2. Electromyography (EMG)
      1. Chronic entrapment Neuropathy
  3. Advanced Imaging (third line)
    1. Peripheral nerve Ultrasound
      1. Evaluate for compression Neuropathy etiologies
    2. Wrist MRI
      1. Indicated in refractory and nondiagnostic cases
      2. Evaluates broad causes of Wrist Pain

X. Management

  1. See Carpal Tunnel Syndrome
  2. Avoid local Corticosteroid Injection
  3. Pad volar wrist
  4. Splint wrist in neutral position
  5. Avoid exacerbating factors
  6. Surgical intervention is rare

XI. Course

  1. Anticipate 6 month course

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Ontology: Guyon Syndrome (C0393886)

Concepts Disease or Syndrome (T047)
MSH D017769
SnomedCT 230632002, 193134004
English Ulnar nerve entrapmen at wrist, Ulnar Nerve Entrapment at the Wrist, Syndrome, Guyon, Syndromes, Guyon, Guyon Syndromes, Canal of Guyon compression, Ulnar nerve entrapment at wrist, Ulnar nerve entrapment at wrist (disorder), Guyon Syndrome
Portuguese Síndrome de Guyon
Spanish Síndrome de Guyon, compresión de nervio cubital a nivel de la muñeca (trastorno), atrapamiento del nervio cubital en el canal de Guyon, atrapamiento del nervio cubital a nivel de la muñeca, atrapamiento del nervio cubital a nivel de la muñeca (trastorno), compresión de nervio cubital a nivel de la muñeca
French Syndrome de la loge de Guyon, Compression du nerf ulnaire au poignet, Syndrome de compression du nerf ulnaire au poignet
German Guyon-Syndrom
Norwegian Entrapment av ulnarisnerven ved håndleddet, Guyons syndrom, Entrapment av ulnarisnerven ved handleddet
Italian Sindrome del canale di Guyon, Compressione del nervo ulnare al polso
Dutch Guyon-syndroom

Ontology: Ulnar Nerve Entrapment Syndrome (C0751658)

Concepts Disease or Syndrome (T047)
MSH D017769
SnomedCT 193135003, 277188003
English Ulnar Nerve Entrapment, Entrapment, Ulnar Nerve, Entrapments, Ulnar Nerve, Nerve Entrapment, Ulnar, Ulnar Nerve Entrapments, Entrapment Syndrome, Ulnar Nerve, ulnar entrapment nerve, entrapment nerve ulnar, ulnar nerve entrapment, Ulnar nerve entrapment, Ulnar nerve entrapment (disorder), neuropathy; entrapment, nerve, ulnar, Ulnar Nerve Entrapment Syndrome
French Compression du nerf ulnaire
Spanish atrapamiento del nervio cubital, compresión de nervio cubital, compresión de nervio cubital (trastorno), atrapamiento del nervio cubital (trastorno)
Norwegian Entrapment av ulnarisnerven
Italian Intrappolamento del nervo ulnare, Sindrome da intrappolamento del nervo ulnare
Dutch neuropathie; inklemming, nervus, ulnaris

Ontology: Ulnar neuropathy at wrist (C3662056)

Concepts Disease or Syndrome (T047)
SnomedCT 68861000119103
English Ulnar neuropathy at wrist (disorder), Ulnar neuropathy at wrist
Spanish neuropatía cubital a nivel de la muñeca (trastorno), neuropatía cubital a nivel de la muñeca