Background

Known to be one of the four major anastomoses between the median (MN) and ulnar (UN) nerves, the Martin-Gruber Anastomosis (MGA) has drawn much attention. Although previous studies have reported data regarding its prevalence, pattern and associated function, there is much variation within the given data. This present study’s aim is to dive further via dissections to further enhance our understanding of both the prevalence and patterns of the MGA.

Methods

Human cadaveric forearms (n = 66) were carefully dissected in the anatomy labs of Tilman J. Fertitta Family College of Medicine (TJFFCOM) and Baylor College of Medicine (BCM) for identification of various MGA nerve pathways. MGA patterns (Type I, Type II Type III) were photographed, documented, and stored. They were then compared to previous literature and studies for assessment of prevalence and pattern types.

Results

The MGA prevalence found within this study was 42%. Type I pattern anastomosis was measured to have approximately 54% prevalence. Type II showed the lowest prevalence in pattern type at 14% prevalence. Type III was found to be at 32% prevalence. It was also noted that unilateral MGA distribution was at 60% (n = 12) compared to bilateral at 40% (n = 8). Furthermore, bilateral distribution often showed congruence within pattern type.

Conclusion

It was noted that the prevalence found within this study seemed significantly higher compared to the reported median within previous literature (42% vs 20%). A notable highlight that resembled previous literature was the high occurrence of MGA buried within the flexor digitorum profundus (FDP) muscle.

The MGA has significant clinical implications for iatrogenic injuries. Exploring the connectional relationship between MGA and associated structures may provide further insights in both prevention and treatment of related injuries including Carpal Tunnel Syndrome, peripheral neuropathies, and nerve transplant.

However, it is noted that Type I pattern is often fibrous due to its embedding nature within the muscle. Often, there were findings that seemed to resemble Type I or II pattern types but could not adequately be confirmed as true MGA incidence. Due to this interesting finding, underlying nerve connections and structures can be further researched to provide additional explanation.