Martin Gruber anastomosis is the connection between the median nerve and ulnar nerve in the forearm which normally are not connected.
In most of cases Anterior interosseous nerve (AIN) is connected to the ulnar nerve in the forearm.
The clinical picture of the patient with nerve injury will present as an atypical presentation to other patients.
A median nerve lesion above communicating branch will affect the median nerve muscles of the hand but a lesion below anastomosis will not affect the median nerve and spare thenar motor intrinsic muscles of the hand which is supplied by the median nerve.
However, the ulnar nerve lesion above communicating area produces an unusual pattern of intrinsic muscle paralysis.
Lesion to the ulnar nerve at the wrist will cause a severe deficit of hand function which is greater than expected
Incidence of Martin Gruber anastomosis
Around 15%
Classifications of Martin Gruber anastomosis
| Types | Features |
|---|---|
| Type I | Communication occurs from AIN to the Ulnar nerve |
| Type II | Communication occurs from the median nerve before division to the Ulnar nerve |
| Type III | Communicating branches from median/AIN and ulnar nerve form a common branch |
| Type IV | Communication occurs from AIN/ Median nerve to Ulnar nerve as a bifurcation in ulnar nerve |
Other Important anastomosis:
Marinacci anastomosis
Ulnar to median anastomosis (reverse MGA)
Riche-cannieu anastomosis
Anastomosis between the deep branch of the ulnar to a recurrent branch of the median nerve
Berrettini Anastomosis
Anastomosis between communicating between the digital nerve (sensory nerves) arising from the ulnar and median nerve in the hand
