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Year : 2021  |  Volume : 69  |  Issue : 4  |  Page : 956-

Commentary on Prevalence of Martin–Gruber Anastomosis in Healthy Subjects: An Electrophysiological Study from Raigarh, Chhattisgarh

Manish Singh Sharma 
 Mayo Clinic Health System, Mankato, MN, USA

Correspondence Address:
Dr. Manish Singh Sharma
Mayo Clinic Health System, Mankato, MN

How to cite this article:
Sharma MS. Commentary on Prevalence of Martin–Gruber Anastomosis in Healthy Subjects: An Electrophysiological Study from Raigarh, Chhattisgarh.Neurol India 2021;69:956-956

How to cite this URL:
Sharma MS. Commentary on Prevalence of Martin–Gruber Anastomosis in Healthy Subjects: An Electrophysiological Study from Raigarh, Chhattisgarh. Neurol India [serial online] 2021 [cited 2021 Dec 3 ];69:956-956
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Full Text

Sur et al.[1] determined that there was electrophysiological evidence of an Martin–Gruber (MG) anastomosis in 16% of 280 forearms affecting 21% of 140 subjects. This was bilateral in 10% of all subjects. MG anastomosis describes a neural connection with the transfer of typical motor fascicles from the median nerve to the ulnar nerve in the forearm. The connection is usually single but duplications may occur. These arise from the median nerve trunk and branch to the superficial forearm flexor muscles or the anterior interosseous nerve.[2] These studies add to the wealth of data available from India and correlates with that available from meta-analyses.[3],[4]

The MG anastomosis is by far the commonest of those in the upper extremity and, along with the Marinacci, Riche–Cannieu, and Berrettini presentations, adds to the variability of innervation of upper extremity muscles in the human body.[5] Needless to state, a clear understanding of these variations is critical to the clinical and electrophysiological evaluation of nerve injuries. These anastomoses can explain why patients with ulnar nerve injuries in the elbow may not manifest intrinsic hand muscle wasting and dysfunction, and patients with severe carpal tunnel syndrome may have preserved muscle strength, no atrophy, and normal motor velocities. An incorrect diagnosis of an ulnar nerve conduction block may result in an unindicated exploration with an iatrogenic injury, especially after transposition as these connections cannot be interrupted.[6] Additionally, intramuscular variations supplying the flexor digitorum profundus may prove to be a point of nerve compression.[1]

In practice, ultrasound has evolved rapidly to become an invaluable adjunct to electrophysiological studies. It is exciting to note that these anastomoses can be directly visualized using this modality.[7]

To conclude, there is a 1 in 5 chance of encountering aberrant anatomy in Indian patients who present with nerve disorders. The eventual diagnosis and localization of these, in my opinion, is team-based. This is primarily determined by sound clinical judgment supplemented by electrophysiological and radiological studies performed by skilled and knowledgeable colleagues.


1Sur A, Sinha MM, Ughade JM. Prevalence of martin-gruber anastomosis in healthy subjects: An electrophysiological study from Raigarh, Chhattisgarh. Neurol India XX; XX: XX.
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3Kaur N, Singla RK, Kullar JS. Martin-Gruber anastomosis- A cadaveric study in North Indian Population. J Clin Diagn Res 2016;10:AC09-11.
4Roy J, Henry BM, Pekala PA, Vikse J, Saganiak K, Walocha JA, et al. Median and ulnar nerve anastomoses in the upper limb: A meta-analysis. Muscle Nerve 2016;54:36-47.
5Smith JL, Siddiqui SA, Ebraheim NA. Comprehensive summary of anastomoses between the median and ulnar nerves in the forearm and hand. J Hand Microsurg 2019;11:1-5.
6Isaković E, Delić J, Bajtarević A. Martin-Gruber anastomosis and transposition in cubital tunnel. Bosn J Basic Med Sci 2007;7:71-3.
7Gans P, Van Alfen N. Nerve ultrasound showing Martin-Gruber anastomosis. Muscle Nerve 2017;56:E46-7.