title: Median-ulnar anastomosis to thenar, hypothenar, and first dorsal interosseous muscles: collision technique confirmation.
abstract: Median-ulnar anastomosis (Martin-Gruber anastomosis; MGA) is traditionally diagnosed based upon changes in compound muscle action potential (CMAP) amplitude following proximal stimulation. We describe a rare patient with a MGA innervating thenar, hypothenar, and first dorsal interosseous muscles. Proximal stimulation, however, evoked CMAPs with striking changes in morphology and area but only minimal amplitude changes, due to concomitant diagnoses of carpal tunnel syndrome and polyneuropathy. Collision studies were therefore required for diagnostic confirmation of the MGA.
authors.affiliation: Department of Neurology, Saint Vincents Hospital and Medical Center of New York, NY 10011, USA.
authors.forename: H W
authors.initials: HW
authors.lastname: Sander
authors.forename: C
authors.initials: C
authors.lastname: Quinto
authors.forename: S
authors.initials: S
authors.lastname: Chokroverty
mesh_terms: D000200:Action Potentials; D001132:Arm; D002349:Carpal Tunnel Syndrome / Q000150:complications; D004558:Electric Stimulation; D004568:Electrodiagnosis; D004576:Electromyography / Q000379:methods*; D006225:Hand; D006801:Humans; D007866:Leg; D008297:Male; D008475:Median Nerve / Q000002:abnormalities* / Q000503:physiopathology; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation*; D010523:Peripheral Nervous System Diseases / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D012677:Sensation / Q000502:physiology; D013933:Thumb; D014459:Ulnar Nerve / Q000002:abnormalities* / Q000503:physiopathology