Type III Guyon Syndrome in 'B Boy' Break-Dancer: A Case Report

Abstract

Although the musculoskeletal injuries associated with break-dancing which is gaining more popularity among adolescent and young people has been reported, the report regarding a peripheral nerve injury associated with breakdance is scarce. We report a rare case of a young amateur break-dancer, 'b-boy' who suffered from a painful paresthesia in his left hand, later diagnosed as type III Guyon's canal syndrome. A 23-year-old, right handed college man presented with a tenderness over the left hypothenar eminence and painful paresthesia over the ring and little fingers of 3 months duration. He trained himself as an amateur 'b boy' break-dancer for the last 10 months. Conservative management under the diagnosis of wrist sprain before presentation did not improve his hand pain. An magnetic resonance imaging and electrodiagnostic study revealed that painful paresthesia was caused by type III Guyon's canal syndrome, and 4 weeks of corticosteroid treatment was given with resolution of pain and paresthesia.

Keywords: Athletic injuries; Ulnar nerve; Ulnar nerve compression syndromes.

FIGURE 1. Break-dance posture and magnetic resonance imaging findings of type III Guyon's canal syndrome. A photograph showing a 'freeze', one of several stereotypical movements of break-dance which might be stressful to the wrist (A). T2-weighted axial (B) and fat-suppressed T1-weighted axial images (C) of the Guyon's canal showing the ulnar nerve (white arrow) and the ulnar artery (black arrow). There was subtle enhancement of the ulnar nerve. Note right side, the T2 coronal images taken from the scout images corresponding the level of axial images.

FIGURE 2. Schematic drawings showing the anatomical differences, depending on the types of Guyon's canal syndromes. A: Type I Guyon's canal syndrome, which is related to the compression of proximal part of Guyon's canal, that causes motor weakness of ulnar innervated muscle and sensory loss in the palmar surfaces of the hypothenar eminence and the fourth and fifth fingers. B: Type II Guyon's canal syndrome, results from the compression of the deep motor branch, leads to the weakness of ulnar innervated muscle and spares sensation. C: Type III Guyon's canal syndrome, only causes sensory loss in the little finger's palmar surface and the ring finger's ulnar side and spares motor (bold full line: the potential site of injuries to the ulnar nerve and its distal symptomatic branches).