Topic
Review Topic
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Evidence
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Snapshot
  • A 36-year-old man presents to his primary care physician due to hand weakness. He reports that his symptoms are accompanied by "tingling" of the 4th and 5th digits. He says that his symptoms worsen when placing the phone to his ear for a long period of time or resting on his elbow. He does not recall any trauma to the wrist or elbow but reports elbow pain. His social history is significant for working as a construction worker. On physical exam, the patient has decreased grip strength on the right arm, as well as a decreased sensation on the 4th and 5th digit. 
Introduction
  • Anatomy
    • the ulnar nerve arises from the C8 and T1 anterior rami of the brachial plexus 
      • above the elbow
        • the ulnar nerve courses medially
      • at the elbow
        • the ulnar nerve courses posteriorly of the medial epicondyle before entering the forearm
      • at the forearm
        • the ulnar nerve branches to provide
          • motor innervation to the 
            • flexor carpi ulnaris
            • flexor digitorum profundus
          • sensory information after branching in the forearm to the
            • palmar ulnar aspect of the hand (by the palmar cutaneous branch)
            • dorsal ulnar aspect of the hand (by the dorsal cutaneous branch)
      • at the wrist
        • the ulnar nerve enters Guyon canal, which travels along the ulnar artery
          • components of Guyon canal
            • floor of the canal
              • tranverse carpal ligament
              • pisohamate ligament
            • roof of the canal
              • palmar fascia
              • palmaris brevis muscle
      • in the hand
        • the ulnar nerve branches into superficial and deep branches
Ulnar Neuropathies
 
Ulnar Neuropathies
Location Etiology Presentation
Elbow
  • Injury to the medial epicondyle
  • Compression in the cubital tunnel
    • cubital tunnel syndrome
  • Paralysis of the
    • flexor carpi ulnaris
    • flexor digitorum profundus (medial half)
    • interossei
      • impaired abduction and adduction
    • lumbricals (medial two)
      • weakened movement of the 4th and 5th digit
  • Sensory impairment in all regions supplied by the ulnar nerve 
  • Unable to grip paper when placed between the fingers 
Wrist
  • Laceration of the wrist
  • Paralysis of the
    • interossei
      • impaired abduction and adduction
    • lumbricals (medial two)
      • weakened movement of the 4th and 5th digit
  • Unable to grip paper when placed between the fingers
  • Ulnar claw 
  • Sensory 
    • impairment of the
      • palmar and superficial branches
      • palmar side of the medial one and half fingers (5th and 1/2 of 4th digit)
    • preservation of the
      • dorsal branch
 
 

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