Aim. To study of anatomical and topographic features and the intrafascicular structure of the thoracodorsal nerve trunk in the brachial plexus. Methods. The study was performed on the brachial plexus preparations of 80 male and female corpses. Short and long branches, secondary bundles, primary trunks, spinal nerves, anterior and posterior roots of the spinal cord were layer-by-layer anatomically prepared from brachial plexus. The angles of inclination from the arising site of the thoracodorsal nerve, the topography throughout and after entering the latissimus dorsi muscle were studied. The length and thickness of the thoracodorsal nerve, including the extramuscular and intramuscular parts, were measured. After isolation and fixation of the preparations, intrafascicular dissection of the thoracodorsal nerve was performed throughout the brachial plexus, by using microsurgical instruments and a binocular magnifier. Results. The length of the thoracodorsal nerve consists of extramuscular and intramuscular parts and was equal to 17.9 cm, of which the extra-muscular part was three-quarters of the total length of the nerve. The nerve trunk dissection revealed that the thoracodorsal nerve consists of 14 nerve fascicles and most frequently, in 46.2% of preparations, the thoracodorsal nerve arises from the C7 nerve root. The presence of motor and sensory portions of nerve fibers in the thoracodorsal nerve was found. In 90.2% of the preparations, the motor portion was located in the posterior-lateral part of the nerve and sensory in the anterior-medial. In most cases, both the sensory and motor fascicles arose from C7, or motor fascicle from C7 and sensory from C8. Conclusion. The intrafascicular dissection of the thoracodorsal nerve revealed microtopography of the sensitive and motor portions of nerve fibers in the nerve and along the entire length of the brachial plexus; in breast reconstruction, after mastectomy with thoracodorsal flap for the preservation of afferent innervation, it is recommended to cross only motor fibers of the thoracodorsal nerve.

Aim. To assess the anatomical possibility of the use of the thoracodorsal nerve as a donor for nerve transfer to the musculocutaneous nerve. Methods. Anatomical dissection of the brachial plexus with layer-by-layer dissection of secondary bundles, short and long branches was performed in 121 male and female corpses. The localization of the origin of thoracodorsal and musculocutaneous nerves relative to the clavicle, the takeoff angle (degrees) from the secondary bundle, the length (in centimeters) of the nerves from the site of origin to the latissimus dorsi muscle entry point and the perforation of the coracobrachialis muscle, respectively, were investigated. The length of the thoracodorsal nerve with and without extramuscular branches was studied separately. Results. It was revealed that, in 58.7% of cases, the thoracodorsal nerve has the optimal length required for transposition to the musculocutaneous nerve. The excess length of the thoracodorsal nerve was between 0.1 and 9.1 cm. In 41.3% of cases, the length of the thoracodorsal nerve is not enough for transposition. Of these, in 17.4% of cases, the shortage of the length of the thoracodorsal nerve was 2 cm or less, which categorically does not allow its transfer to the musculocutaneous nerve. Only in 5% of cases, the length of the nerve was not enough for transposition in the use of the thoracodorsal nerve with extramuscular branches. Conclusion. Due to tension in many cases, the thoracodorsal nerve transfer to the musculocutaneous nerve can be performed with difficulty, and in some cases it is impossible, solving the problem in this category of people dictates the development of new surgical techniques with the thoracodorsal nerve or the use of another nerve as a donor.