Published online: 2021-03-29 THIEME 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 Marcelo Medeiros Felippe1 Renan Salomão Rodrigues1 Thais Baccarini Santana2 1 Department of Neurosurgery, Hospital Municipal Dr. José de Address for correspondence Renan Salomão Rodrigues, MD, Carvalho Florence, São Jose dos Campos, SP, Brazil Departamento de Neurocirurgia do Hospital Municipal Dr. José de 2 Department of Otorhinolaryngology, Hospital Estadual dos CarvalhoFlorence,RuaJorgedeOliveira Coutinho 280, apt. 133, São Servidores do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil José dos Campos, São Paulo, SP, 12246-060, Brazil (e-mail:
[email protected]). Arq Bras Neurocir Abstract 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 anatomi- Keywords cal pattern – Berrettini: Connection between the common digital nerves of the ulnar ► Martin Gruber and median nerves; and Riche-Cannieu: anastomosis between the recurrent branch of ► Marinacci the median nerve and the deep branch of the ulnar nerve. Due to these connection ► Berrettini patterns, musculoskeletal disorders and neuropathies can be misinterpreted, and ► Riche-Cannieu nerve injuries during surgery may occur, without the knowledge of these anastomoses.