Revista chilena de anatomía
versión impresa ISSN 0716-9868
OLAVE, E.; GABRIELLI, C.; BRAGA, M. T. T. y DEL SOL, M.. BIOMETRIC ASPECTS OF THE MOTOR BRANCHES OF THE MUSCULOCUTANEOUS NERVE TO THE BRACHIAL MUSCLE. Rev. chil. anat. [online]. 2002, vol.20, n.2, pp.231-236. ISSN 0716-9868. http://dx.doi.org/10.4067/S0716-98682002000200019.
SUMMARY: The motor points are the penetration place of the motor fibers in the muscle through the epimisio, that is why its knowledge is of great importance, mainly when an atrophied muscle require to be electro-stimulated. In relation to this subject, we studied the innervation of the brachial muscle, describing in detail the branches coming from the musculocutaneous nerve, taking into account the levels where they originate, their final distribution and the penetration level in the muscular tissue. For this purpose, we have studied 46 upper limbs of 23 formolized corpses of Brazilian adult individuals of both sexes.In order to determine the origin and the penetration points of the mentioned muscular branches the biepicondilar line (LBE) was considered as reference. The brachial muscle received branches coming from the musculocutaneous nerve in all cases (100%); 1 branch was found in 15 cases (65.2%) at the right side and in 18 cases (78.3%) at the left side. With 2 branches, 6 cases (26.1%) were observed at the right side and 2 cases (8.7%) at the left side. There were also 3 and 4 branches. When there was only 1 branch, its origin level at the right side was of 130.1 ± 13.3 mm on average in respect to LBE and of 127.88 ± 12.0 mm at the left side. When there were 2 branches, their origin level was 126.2 ± 14.5 mm on average for the proximal and of 100.2 ± 37.1 mm for the distal, always in respect to LBE. At the left side, as there were only 2 cases, the average was not calculated. In relation to the entrance point in the muscular vientre, most of then did it through the medial portion of the muscle, finding that, when there was a single branch, 13 of then had this characteristic at the right side and 15 at the left side. Almost all these nerves subdivided in smaller branches (secondary) finding 2, 3, 4 and 5 of them, which penetrated in the muscular tissue at different levels. These data may serve as reference for reinnervation surgeries, selective blocking on motor points and physiotherapeutic treatments in the arm
Palabras clave : Anatomy; Brachial muscle; Innervation; Muscular branches.