CC BY-NC-ND 4.0 · Arquivos Brasileiros de Neurocirurgia: Brazilian Neurosurgery 2021; 40(02): e152-e158
DOI: 10.1055/s-0041-1724044
Review Article | Artigo de Revisão

Anastomosis Patterns between the Median and Ulnar Nerves in the Upper Limbs

Padrões de anastomose entre os nervos mediano e ulnar nos membros superiores
1   Department of Neurosurgery, Hospital Municipal Dr. José de Carvalho Florence, São Jose dos Campos, SP, Brazil
1   Department of Neurosurgery, Hospital Municipal Dr. José de Carvalho Florence, São Jose dos Campos, SP, Brazil
2   Department of Otorhinolaryngology, Hospital Estadual dos Servidores do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
› Author Affiliations


There are four types of anastomoses between the median and ulnar nerves in the upper limbs. It consists of crossings of axons that produce changes in the innervation of the upper limbs, mainly in the intrinsic muscles of the hand. The forearm has two anatomical changes – Martin-Gruber: branch originating close to the median nerve joining distally to the ulnar nerve; and Marinacci: branch originating close to the ulnar nerve and distally joining the median nerve. The hand also has two types of anastomoses, which are more common, and sometimes considered a normal anatomical pattern – Berrettini: Connection between the common digital nerves of the ulnar and median nerves; and Riche-Cannieu: anastomosis between the recurrent branch of the median nerve and the deep branch of the ulnar nerve. Due to these connection patterns, musculoskeletal disorders and neuropathies can be misinterpreted, and nerve injuries during surgery may occur, without the knowledge of these anastomoses. Therefore, knowledge of them is essential for the clinical practice. The purpose of the present review is to provide important information about each type of anastomosis of the median and ulnar nerves in the forearm and hand.


Existem quatro tipos de anastomoses entre os nervos mediano e ulnar nos membros superiores. Elas consistem em cruzamentos de axônios que produzem mudanças na inervação dos membros superiores, principalmente na musculatura intrínseca da mão. O antebraço apresenta duas variações anatômicas – Martin-Gruber: ramo que se origina proximalmente ao nervo mediano e se une distalmente ao nervo ulnar; e Marinacci: ramo que se origina proximalmente ao nervo ulnar e se une distalmente ao nervo mediano. A mão apresenta também dois tipos de anastomoses, mais comuns, por vezes considerados padrão anatômico normal – Berrettini: conexão entre os nervos digitais comuns dos nervos ulnar e mediano; e Riche-Cannieu: anastomose entre o ramo recorrente do nervo mediano e o ramo profundo do nervo ulnar. Devido a esses padrões de conexões, distúrbios musculoesqueléticos e neuropatias podem ser mal interpretadas, e lesões nervosas durante as cirurgias podem ocorrer, sem o conhecimento dessas anastomoses. Portanto, o conhecimento delas é fundamental para a prática clínica. O objetivo desta revisão é fornecer informações importantes acerca de cada tipo de anastomose dos nervos mediano e ulnar no antebraço e na mão.

Publication History

Received: 13 July 2020

Accepted: 16 November 2020

Article published online:
29 March 2021

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