Anastomosis Between the Deep Branch of Ulnar Nerve and a Branch of the Median Nerve (Cannieu-Riché Anastomosis) and Thenar Muscles Innervation. Anatomical Study and Clinical Implications

Abstract

SUMMARY:The aim of this paper was to report the incidences of the anastomosis between deep branch of ulnar nerve and a branch of the median nerve commonly named Cannieu-Riché anastomosis (CRA) and thenar muscles innervation. The anatomical dissection of 80 limbs from 40 fresh adult cadavers were performed in the Department of Anatomy at the Medical School of the Catholic University of São Paulo. The incidence of CRA and thenar muscle innervation were studied. The CRA was found in all of the dissected hands (100 %). The abdutor pollicis brevis and the opponens pollicis muscle are innervated exclusively by median nerve in all dissected hands. The superficial head of flexor pollicis brevis was innervated by the median nerve in of 56 the hands (70 %), in 24 (30 %) it had double innervation (median nerve and deep branch of ulnar nerve). The deep head of flexor pollicis brevis were absent in 11 hands (14 %), in 52 hands (65 %), a double innervation was observed. In 14 (17.5 %) exclusively by deep branch of ulnar nerve and in 3 hands (3.6 %) exclusively by a branch of median nerve. The oblique head of adductor pollicis muscle was innervated only by deep branch of ulnar nerve in 66 hands (82 %) of dissected hands, 14 (17.5 %) had a double innervation. The transverse head of adductor pollicis was innervated exclusively by deep branch of ulnar nerve in 77 hands (96.4 %), and in 3 (3.6 %) had a double innervation. According to our study the pattern of innervation was more frequent in relation to the flexor pollicis brevis muscle and should be considered as a normal pattern, in that the superficial head receives innervation of branches of median nerve, and the deep head receives innervation of deep branch of ulnar nerve and branches of median nerve (dual innervation). The abductor pollicis brevis and opponens pollicis received innervation exclusively by median nerve. Both the oblique and transverse head of adductor pollicis exclusively by ulnar nerve. The RCA was found in all of the dissected hands (100 %).KEY WORDS: Median nerve; Ulnar nerve; Hand/Innervation. INTRODUCCIÓNThe basic anatomy of the median and ulnar nerves in the upper limb, particularly in the hand is well described in textbooks. The variety of clinical aspects observed in the isolated lesions of median and ulnar nerves, does not agree with the classic pattern of innervation of the muscles from the thenar region. A better knowledge of the anatomical variations of these nerves helps to understand both anatomic variations and paradoxic complaints of sensory and motor

Communicating Branches Between the Median and Ulnar Nerves. Proposal for Inclusion in Terminologia Anatomica

“…The prevalence rate reported for this branch is variable, reaching 79.1 % of the population (Fig. 2, A) (Wolf-Heidegger, 1962;Roy et al;Wynter & Dissanbandara;Caetano et al, 2018).…”

Unilateral Absence and Contralateral Communication Between Musculocutaneous and Median Nerve and Its Clinical Significance

“…Martin Gruber anastomosis which is the nerve communication between the median and ulnar nerve is reported by many authors when reviewed the literature [1]. Berretini anastomosis, nerve communications between sensory branches of median and ulnar nerve in palm while Cannieu and Riché anastomosis between the thenar motor branch of the median nerve and the deep branch of the ulnar nerve in the palm of the hand have been described in many studies [2,3].…”