Electrophysiological Evaluation of the Incidence of Martin-Gruber Anastomosis in Healthy Bosnian Population

Abstract

Background: Martin-Gruber anastomosis (MGA) is the well known anostomosis that occur at the various levels between the median and ulnar nerves. This anastomosis involves axons leaving either the main trunk of median nerve or the anterior interosseous nerve, crossing through the forearm to join the ulnar nerve. Knowledge of the incidence of this anastomosis is necessary because MGA can cause confusion in the assesment of nerve injuries and compressive neuropathies. Aim: We aimed to assess the occurance and motor velocities of median to ulnar nerve communication (MGA) in the forearm of Bosnian population by electrophysiological examinations. Material and Methods: One hundred and twenty forearms from a series of 60 volunteers (25 females, 35 males, 23-78 years of age) were studied electrophysiologically using needle recording electrodes. Volunteers with peripheral neuropathies were excluded from the study. Needle recording electrodes were places on the thenar and hypothenar muscles. The median and ulnar nerves were stimulated supramaximally at the wrist and the elbow and compound muscle action potentials (CMAPs) were recorded as well as motor conduction velocities of median and ulnar nerves. Results: Martin-Gruber anastomosis was found in 27 of 120 forearms; it was bilateral in 7 and unilateral in 13, on the right side in nine and on the left side in four forearms. There were no significant sexual differences in the incidence. In MGA, when stimulating median nerve the respond of abductor digiti minimi was registered in 11, whereas the respond of opponens pollicis when stimulating ulnar nerve was registered in 18 subjects. This finding was statistically significant. Conclusion: With high incidence of MGA in Bosnian population, it is necessary to be aware of the existance of this anomaly, location and its possible presentation.