Thoracic outlet syndrome is a group of disorders that affect the upper extremity and neck, resulting in compression of the neurovascular bundle that exits the thoracic outlet. Depending on the type of compressed structure, the arterial, venous, and neurogenic forms of TOS are distinguished. In some populations, e.g., in certain groups of athletes, some sources report incidence rates as high as about 80 cases per 1000 people, while in the general population, it is equal to 2–4 per 1000. Although the pathogenesis of this condition appears relatively simple, there are a very large number of overlapping risk factors that drive such a high incidence in certain risk groups. Undoubtedly, a thorough knowledge of them and their etiology is essential to estimate the risk of TOS or make a quick and accurate diagnosis.

The diagnostic process that allows pronator syndrome to be differentiated reliably from carpal tunnel syndrome remains a challenge for clinicians, as evidenced by the most common cause of pronator syndrome misdiagnosis: carpal tunnel syndrome. Pronator syndrome can be caused by compression of the median nerve as it passes through the anatomical structures of the forearm, while carpal tunnel syndrome refers to one particular topographic area within which compression occurs, the carpal tunnel. The present narrative review is a complex clinical comparison of the two syndromes with their anatomical backgrounds involving topographical relationships, morphology, clinical picture, differential diagnosis, and therapeutic options. It discusses the most frequently used diagnostic techniques and their correct interpretations. Its main goal is to provide an up-to-date picture of the current understanding of the disease processes and their etiologies, to establish an appropriate diagnosis, and introduce relevant treatment benefiting the patient.

The main aim of this study is to present, describe and compare the most significant anatomical classifications of the internal iliac artery (IIA) and its branches, their pros and cons, to relate them to clinical practice and note their clinical importance, and to offer a new classification based on number of main vessels origins. Many classifications covering the detailed morphology of the IIA have been developed, focusing on the destination of vessels making it possible to determine the name and type of branching precisely. However, because the allocation criteria are overdetailed and of doubtful accuracy, these classifications have become impractical for clinical practice and advanced statistical calculations. The argument of this research paper is that highly variable vascularized regions should be classified from either an anatomical point of view to determine detailed morphology aspects or a clinical perspective. Presented classification proposes unification of many branching types presented among various classifications, which look identical when determining the origin pattern from the main vessel and differ only in the destination point of the vessel, what brings clarity and increases the statistical usefulness of the collected data. This should translate into better cooperation between scientists and clinicians and thus benefit patients. The paper proposes a new, clinically useful classification based on the model of vessel origins from the main stem. The IIA is the main vascular supply to the pelvic region, so precise knowledge of origin and its branching pattern is essential for all clinicians, especially for general and orthopaedic surgeons, gynecologists, obstetricians and urologists.