Innervation of the Brachioradialis Muscle in Brazilian Individuals: Anatomo-clinical aspects of the Biometry of Origin and Nervous Distribution

The nerve for the brachioradialis muscle (BR) has been used in nerve transfers for recoveries in functions of the hand as a consequence of lesions affecting the brachial plexus. With the purpose of investigating the number and biometric location of the primary branches coming from the radial nerve and motor points with respect to a reference point located in the elbow region, thirty upper limbs of Brazilian adult individuals from the State University of Sciences of Saude de Alagoas, Maceio, Brazil were used. The samples were fixed in 10 % formaldehyde solution, of which 15 were right and 15 left. As a reference point, a line was used that passed through the most prominent parts of the humeral epicondyls, bi-epicondilar line (BEL). With respect to the nervous origin for the BR muscle, all the branches originated from the radial nerve (RN). The average number of primary branches (PB) was 1.53 (SD 0.73). In 18 samples (60 %) only one PB was observed; in 8 cases (26.7 %) 2 PB were found, while in 4 cases (13.3 %) of the sample 3 PB were observed. Regarding the biometric location of the origins of PB, it is important to mention that all were located proximal to the BEL. On average, these were located at 38 mm (SD 0.9); 29 mm (DS 1.2) and 22 mm (DS 1.0) for the first, second and third PB, respectively. In relation to the motor points (MP), in 4 cases (13 %) 1 MP was observed as direct penetration of the PB, in 13 cases (43 %) there were 2 MP, in 8 cases (27 %) they found 3 MP and in 5 cases (17 %) 4 MP were observed. In three cases (10 %) the innervation towards the BR muscle emitted nerve fillets towards the extensor carpi radialis longus muscle. The results presented in this investigation are an important contribution to nerve blocks, electrical stimulations and nerve transfers