Martin-Gruber Anastomosis Explained

A Martin-Gruber anastomosis (MGA) is a connection from the median nerve to the ulnar nerve in the forearm. An anastomosis occurs when two structures that normally are not connected have a connection. In this case the connection is a nerve. The Martin-Gruber anastomosis is most common anastomosis that occurs between these two nerves.[1] This connection carries motor axons which innervate some of the usually ulnar nerve innervated intrinsic muscles.

This inconstant pattern of connection can serve as explanation for a difficult or challenging differential diagnosis.[2] In one study,[3] the MGA was found in 22.9% of cadaver specimens, while another found the incidence at ~11%.[4] This relatively high incidence demonstrates the necessity for healthcare specialists to factor the MGA into their diagnoses.

Types

There are six types of Martin-Gruber anastomoses.

Clinical Significance

In the setting of proximal ulnar nerve injury, a Martin-Gruber anastomosis can prevent the complete paralysis of the intrinsic muscles of the hand.

References

Notes and References

  1. Erdem HR, Ergun S, Erturk C, Ozel S . Electrophysiological Evaluation of the Incidence of Martin-Gruber Anastomosis in Healthy Subjects . Yonsei Medical Journal . 43 . 3 . 291–5 . June 2002 . 12089734 . 10.3349/ymj.2002.43.3.291. free .
  2. Web site: The communications between the ulnar and median nerves in upper limb . Unver Dogan . Nadire . neuroanatomy.org . March 14, 2009 . 2012-09-01.
  3. Rodriguez-Niedenführ M, Vazquez T, Parkin I, Logan B, Sañudo JR . Martin-Gruber anastomosis revisited . Clinical Anatomy . 15 . 2 . 129–34 . March 2002 . 11877791 . 10.1002/ca.1107.
  4. Kaur et al . Martin–Gruber Anastomosis- A Cadaveric Study in North Indian Population . Journal of Clinical and Diagnostic Research . 10 . 2 . AC09–AC11 . Feb 2016 . 27042438 . 10.7860/JCDR/2016/16447.7247 . 4800503 .