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 study anatomical variations of the intra–trunk pathways in the thoracodorsal nerve bundles and to develop a system for their coding.Materials and methods. After fixation in a 2% solution of acetic acid using the MBS-10 stereomicroscope, we performed macro- and microscopic intra-trunk dissection of thoracodorsal nerve bundles in 121 specimens obtained from 105 corpses of males and females who died at the age of 40–97 years. Using the obtained findings, we compiled a database in the MS Excel 12.0 software and determined the number of anatomical variations in absolute and relative (% from 121 specimens) units.Results. The study revealed that the thoracodorsal nerve is a mixed nerve, which consists of 1 motor and 1– 3 sensory bundles that variously pass through the spinal nerves, trunks, and the axillary nerve with the formation of 20 intra-trunk pathways. In 77% of cases, sensory bundles arising from the thoracodorsal nerve pass through the posterior bundle, the posterior division, the middle trunk, and the C7 spinal nerve or the inferior trunk and the C8 spinal nerve. In 22% of cases, the thoracodorsal nerve has one or, rarely, two duplicate sensory pathways besides the main one. In 93% of cases, the motor bundle to the thoracodorsal nerve passes through the C7 spinal nerve and the middle trunk, the posterior division, and the posterior bundle. Coding the anatomical variations of the intra-trunk pathways in the direction of sensory bundle «posterior bundle → posterior division → trunk → spinal nerve; motor bundle ← posterior bundle ← posterior division ← trunk ← spinal nerve allows to briefly yet clearly and fully display the morphological diversity of the nerve anatomy.Conclusion. The identified anatomical variations of the intra-trunk pathways can be useful in the diagnosis of injuries and diseases. They expand indications for the use of spinal nerves, trunks of the brachial plexus, and the thoracodorsal nerve in reconstructive surgery.

Background. Understanding the complexities of formation and structural features of the brachial plexus remains important for diagnosis, effective surgical treatment and regional anesthesia. Aim. To identify variants of the brachial plexus structure and develop a system for their coding. Material and methods. Macroscopic anatomical layer-by-layer and macro-microscopic intratubular dissection of 121 brachial plexus preparations were performed in 105 cadavers of men and women aged 40100 years. A database was formed from the obtained indicators in the MS Excel 2012 program, and their processing was carried out using Statistica for Windows 12. All indicators were tested for the normal distribution using the ShapiroWilco criterion. When describing the studied indicators, the median (Me) and interquartile intervals [Q1, Q3] were determined, as well as the significance of intergroup differences according to the MannWhitney test. Results. It was established that the farther from the spinal cord, the more variants of the macroscopic and macro-microscopic structure of the brachial plexus elements exist: roots 3, trunks 7, divisions 3, bundles 1216, and a total of 20 variants of the general structure were identified. The roots of spinal nerves C6 (66.1%), C7 (66.4%) and C8 (64.2%) take the greatest part in the formation of brachial plexus bundles, 2 times less often C5 (34.8%) and Th1 (33.3%), very rarely C4 (2.5%) and Th2 (0.8%). Reverse coding of variants of the brachial plexus structure in the direction: bundle division trunk (root) allows to briefly and clearly display the entire morphological diversity of the nervous system of the human upper limb. The results obtained should be taken into account when diagnosing injuries, performing regional anesthesia, reconstructive operations, rehabilitation measures, creating neurosimulators, neurochips, and nerve conductors. Conclusion. 20 different variants of the general structure of the human brachial plexus have been identified and a reverse coding system has been developed.

Th e aim of the research. To summarise all available information about the bundle structure of the brachial plexus and the nerves of the upper limb. This systematic review aims to provide a viable basis for fascicular repair of damaged peripheral nerves. Material and methods. Th e search for papers was carried out using Google Scholar, Medline and PubMed electronic databases using the following keywords: “bundle structure of the brachial plexus and nerves of the upper limb”, “fascicular anatomy”, and “fascicular restoration of damaged nerves”. A total of 187 articles were reviewed and 104 articles were deemed relevant according to the inclusion criteria. Results. Th is review gives a detailed description of the five stages of search for knowledge and general features of the bundle structure of the brachial plexus and peripheral nerves of the upper limb. The role of connective tissue in formation of plexuses and stabilisation of the bundle structure has been shown. The variant anatomy of the distal peripheral nerve bundles (shape, size, number and topography) has been described in detail. The role of knowledge about the bundle structure in the fascicular restoration of damaged peripheral nerves of the upper limb is shown. Conclusion. Over the past 250 years, a difficult path has been passed to reveal knowledge and form the idea of the bundle structure of the brachial plexus and peripheral nerves of the upper limb. The knowledge gained has formed the basis for numerous methods of fascicular restoration of damaged nerves. Despite the results achieved, it is required to carry out further research on the organ features and variant anatomy of the bundle structure of all upper limb nerves all the way to the spinal cord.

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.