Purpose: Morphological variations of the brachial artery are quite commonly discovered in routine dissection and have been the subject of many studies. However, there is a need for a clear classification. This work presents morphological variations of the brachial artery, based on numerous case reports and studies created for the appropriate classification and interpretation among surgeons and radiologists. It also discusses the most important clinical aspects of the given varieties. Methods: The research method is based on the combined interpretation of the researches based on numerous publications concerning both the principles of correctly classifying the described morphological variations of the brachial artery and the resulting clinical implications. This work considers atypical variations such as the presence of the superficial brachial artery, brachoradial artery, accessory brachial artery and absence of the brachial artery. Variations of the brachial artery in relation to the external and internal diameter of the vessel have also been discussed. Results: After conducting a complex analysis of the collected data, the fundamental principles for classifying such variability as superficial brachial artery, brachioradial artery and accessory brachial artery were defined. Additionally, clinical implications resulting from the above like the impact of the superficial brachial artery on the median nerve neuropathy and the positive correlation between the brachioradial artery and increased danger of incorrect transradial catheterization were demonstrated. Conclusions: The clinical implications of the atypical arterial pattern within the upper limb are crucial during the angiography and surgical procedures so the variations affect the appropriate diagnosis and surgical intervention. Hence, the knowledge about the morphological variations of the brachial artery should be constantly broadened by radiologists and surgeons to improve the accuracy and effectiveness of the treatment process.

Background/Objectives: Vertebral numbering on limited lumbosacral imaging is difficult when the thoracic or lumbar count varies. The L3 transverse process has been proposed as a landmark because it is often the longest, but this has not been tested across segmentation patterns. This study assessed whether L3 as the level bearing the longest transverse process is independent of thoracic and lumbar vertebral count on whole-spine CT. Methods: Of 499 trauma CT examinations with confirmed numbering, all 49 non-standard thoracolumbar formulas were included, together with 17 C7T12L5 spines that remained after exclusion of transitional and numerical anomalies at every level (n = 66). Bilateral lumbar transverse-process lengths were measured on multiplanar reconstructions. The longest level was identified by morphological and presacral numbering. Associations with thoracic patterns (C7T11, n = 10; C7T12, n = 43; C7T13, n = 13) were tested with the Fisher–Freeman–Halton exact test and Monte Carlo simulation. Nine primary analyses were adjusted with the Holm procedure. Inter-observer agreement was assessed with an intraclass correlation coefficient. Results: In this enriched cohort, L3 was the longest level in 45/66 cases (68.2%) based on the single longest transverse process and 49/66 (74.2%) based on bilateral mean length. These percentages are not population prevalences. Within the C7T12 group, the corresponding proportions were 76.7% and 83.7%, respectively. By bilateral mean length, L3 was longest in 30.0% of C7T11, 83.7% of C7T12 and 76.9% of C7T13 cases (exact p = 0.003, Holm-adjusted p = 0.014). The single-process association did not remain significant after Holm correction (adjusted p = 0.058). The 22nd presacral vertebra showed a comparable dependence on thoracic pattern (Holm-adjusted p = 0.041 and 0.001 for the single-process and bilateral-mean analyses, respectively). Inter-observer ICC was 0.88 for individual transverse-process lengths and 0.93 for bilateral means. Conclusions: Neither L3 nor the 22nd presacral vertebra is a segmentation-independent marker of lumbar identity. Full-spine counting remains necessary when precise numbering is required.

Background/Objectives: Lumbosacral transitional vertebrae (LSTV) are an under-recognized anatomical variant potentially associated with low back pain (LBP). Comparative data on the established Castellvi classification and the more recently proposed Jenkins system are also limited. This study compared LSTV detection by the two systems on routine sacroiliac joint radiographs and evaluated associations with age, LBP, and rheumatologic diagnoses. Methods: This retrospective study included 817 patients who underwent sacroiliac joint radiography at a rheumatology outpatient clinic between 2022 and 2024. Radiographs were reassessed using a standardized protocol. Age-related patterns and alternative transverse process–sacral ala distance thresholds were evaluated. Associations between LSTV and documented LBP were adjusted for age, sex, radiographic sacroiliitis grade, and the presence of a recorded rheumatologic diagnosis. Results: LSTV was identified in 248/817 patients (30.4%) by Castellvi and in 735/817 (90.0%) by Jenkins. The discrepancy was driven predominantly by Type I variants (20.9% vs. 80.5%); after their exclusion, both systems identified the same 77/817 patients (9.4%) as having Types II–IV. Jenkins-positive prevalence rose from 68.4% in patients younger than 20 years to 100% in those aged ≥70 years (Cochran–Armitage Z = 6.80, p < 0.001), whereas no corresponding trend was observed for Castellvi. An exploratory TP–sacral ala threshold of <5 mm reduced Jenkins-positive prevalence to 61.7%. Neither classification was associated with documented LBP after multivariable adjustment. LSTV was not mentioned in any original sacroiliac joint radiology reports. Conclusions: The Castellvi and Jenkins systems yielded markedly different LSTV prevalence estimates, primarily because of their differing Type I criteria. The high prevalence and strong age dependence of Jenkins Type I findings suggest that the 10-mm distance criterion may capture age-dependent anatomical configurations in addition to transitional morphology and highlight the need for independent validation before its broader clinical use.