Clinical repercussions of Martin-Gruber anastomosis: anatomical study

100 forearms of 50 adult cadavers were dissected in an anatomy laboratory. The dissection was performed by means of a midline incision along the entire forearm and the lower third of the upper arm. Two flaps including skin and subcutaneous tissue were folded back on the radial and ulnar sides, respectively.

RESULTS:

Nerve communication between the median and ulnar nerves in the forearm (Martin-Gruber anastomosis) was found in 27 forearms. The anastomosis was classified into six types: type I: anastomosis between the anterior interosseous nerve and the ulnar nerve (n = 9); type II: anastomosis between the anterior interosseous nerve and the ulnar nerve at two points (double anastomosis) (n = 2); type III: anastomosis between the median nerve and the ulnar nerve (n = 4); type IV: anastomosis between branches of the median nerve and ulnar nerve heading toward the flexor digitorum profundus muscle of the fingers; these fascicles form a loop with distal convexity (n = 5); type V: intramuscular anastomosis (n = 5); and type VI: anastomosis between a branch of the median nerve to the flexor digitorum superficialis muscle and the ulnar nerve (n = 2).

CONCLUSION:

Knowledge of the anatomical variations relating to the innervation of the hand has great importance, especially with regard to physical examination, diagnosis, prognosis and surgical treatment. If these variations are not given due regard, errors and other consequences will be inevitable.

Arteriovenous anastomosis/anatomy & histology; Median nerve; Ulnar nerve

Year	Authors	Study	Cases studied	Cases that presented Martin-Gruber anastomosis (%)
1870	Gruber⁴	Anatomical	250	15.2
1893	Thomson⁹	Anatomical	406	15.5
1931	Hirasawa¹⁰	Anatomical	No data	10.5
1976	Kimura et al.¹¹	Electrophysiological	328	17
1981	Srinivasan and Rhodes¹²	Anatomical, genetic	200	15
1992	Uchida and Sugioka¹³	Electrophysiological	47 (cubital syndrome)	17
			87 (normal)	16
1992	Amoiridis²⁶	Electrophysiological	100	32
1993	Nakashima¹⁴	Anatomical	108	21.3
1999	Shu et al.¹⁶	Anatomical, histological	72	23.6
2002	Rodriguez-Niedenfuhr et al.¹⁷	Anatomical	140	13.6
			236	13.1
2005	Lee et al.¹⁸	Anatomical, electrophysiological	102 (anatomical)	39.2
			224 (electrophysiological)	23.2
2015	Our results	Anatomical	100	27

Year	Authors	Classification proposed; anastomosis between the median and ulnar nerves
1893	Thomson⁹	Class I: anterior interosseous nerve and ulnar nerve
		Class II: median nerve and ulnar nerve
		Class III: muscle branch to deep flexor muscle of the fingers

1931	Hirasawa¹⁰	Oblique anastomosis: anterior interosseous nerve and ulnar nerve
		median nerve and ulnar nerve
		Loop anastomosis: muscle branch to deep flexor muscle of the fingers
		Combined anastomosis: combinations between others

1976	Kimura et al.¹¹	Type I: median nerve and ulnar nerve innervating the hypothenar muscle
		Type II: median nerve and ulnar nerve innervating the deep flexor muscle of the fingers
		Type III: median nerve and ulnar nerve innervating the thenar muscle

1981	Srinivasan and Rhodes¹²	Types I, II, VI: anterior interosseous nerve and ulnar nerve or other
		Type III: median nerve and ulnar nerve
		Types IV, V: combinations of others

1992	Uchida and Sugioka¹³	Type I: median nerve and ulnar nerve innervating the hypothenar muscle
		Type II: median nerve and ulnar nerve innervating the thenar muscle
		Type III: median nerve and ulnar nerve innervating the deep flexor muscle of the fingers

1993	Nakashima¹⁴	Type Ia: anterior interosseous nerve and ulnar nerve
		Type Ib: median nerve and ulnar nerve
		Type III: combination of types Ia, Ib and II

1995	Oh et al.¹⁵	Type I: median nerve and ulnar nerve innervating the hypothenar muscle
		Type II: median nerve and ulnar nerve innervating the deep flexor muscle of the fingers
		Type III: median nerve and ulnar nerve innervating the thenar muscle

1999	Shu et al.¹⁶	Type I: anterior interosseous nerve and ulnar nerve
		Type II: median nerve and ulnar nerve
		Type III: muscle branch to deep flexor muscle of the fingers
		Type IV: anterior interosseous nerve and ulnar nerve, muscle branch to deep flexor muscle of the fingers originating from the connection
		Type V: two anastomotic branches

2002	Rodriguez-Niedenfuhr et al.¹⁷	Pattern I: one anastomotic ramus
		Pattern II: two anastomotic rami
		Type A: anastomotic ramus originating from a branch of the median nerve to the nerve of the superficial flexor muscle of the forearm
		Type B: anastomotic ramus originating from the median nerve
		Type C: anastomotic ramus originating from the anterior interosseous nerve

2005	Lee et al.¹⁸	Type I: anterior interosseous nerve and ulnar nerve
		Type II: median nerve and ulnar nerve
		Type III: muscle branch to deep flexor muscle of the fingers
		Type IV: two anastomotic rami from the ulnar nerve or anterior interosseous nerve and ulnar nerve
2015	Our classification	Type I: anterior interosseous nerve and ulnar nerve
		Type II: anterior interosseous nerve and ulnar nerve (double anastomosis)
		Type III: median nerve and ulnar nerve
		Type IV: loop between anterior interosseous nerve and ulnar nerve with branches to deep flexor muscle of the fingers
		Type V: intramuscular anastomosis
		Type VI: branch from the median nerve to the superficial flexor muscle and ulnar nerve

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E-mail: rbo@sbot.org.br

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[1] * Corresponding author. E-mail: cristina_schmitt@hotmail.com (C.S. Cavalheiro).

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Clinical repercussions of Martin-Gruber anastomosis: anatomical study☆ ☆ Work developed in the Department of Surgery, School of Medical and Health Sciences, Sorocaba Campus, Pontifícia Universidade Católica de São Paulo, Sorocaba, SP, Brazil.

OBJECTIVE:

METHOD:

RESULTS:

CONCLUSION:

Clinical repercussions of Martin-Gruber anastomosis: anatomical study^☆ ☆ Work developed in the Department of Surgery, School of Medical and Health Sciences, Sorocaba Campus, Pontifícia Universidade Católica de São Paulo, Sorocaba, SP, Brazil.