Department of Anatomy, Second Faculty of Medicine, Charles University, V Úvalu 84, 150 06 Prague 5, Czech Republic.
Department of Anatomy, Second Faculty of Medicine, Charles University, V Úvalu 84, 150 06 Prague 5, Czech Republic; Department of Health Care Studies, College of Polytechnics, Tolsteho 16, 586 01 Jihlava, Czech Republic.
Ann Anat. 2021 Nov;238:151751. doi: 10.1016/j.aanat.2021.151751. Epub 2021 Apr 30.
The brachial plexus is a complex anatomical structure that gives rise to all the nerves of the upper limb. Its variability is frequently observed and represents a challenge for interventions in the lower neck and axilla. The aim of this study was to present a comprehensive and evidence-based review with meta-analytic techniques on the variability of roots, trunks, divisions and cords of the brachial plexus.
Major medical databases were searched to identify all anatomical studies investigating the variability in the formation of the brachial plexus. Data extracted consisted of demographic information, morphometric parameters, the arrangement of the brachial plexus at the level of the roots, trunks, divisions and cords and the relationship of the brachial plexus to the axillary artery and scalene muscles. The different configurations of the brachial plexus were put into a new classification, and the pooled prevalence of each case was calculated using a random effects model. A sub-analysis on age and geographical location was also performed.
A total of 40 studies (3055 upper limbs) were included in the meta-analysis. The regular arrangement of roots forming trunks was identified in 84% (95% CI 79-89%) of cases. The overall prevalence of the prefixed and postfixed brachial plexus was 11% (95% CI 6-17%) and 1% (95% CI 0-1%), respectively and in less than 0.1% of cases the brachial plexus received a branch from both C4 and T2. For divisions forming cords, the regular arrangement was observed in 96% (95% CI 93-98%) of cases. Additional communicating branches between the components of the brachial plexus appeared in 5% (95% CI 3-7%) of cases. The relationship of the brachial plexus to the axillary artery and scalene muscles was considered regular in 96% (95% CI 89-100%) and 86% (95% CI 66-98%) of cases, respectively. Analysis of the morphometric parameters revealed the proportional consistency between the components forming the plexus during aging.
Knowledge of anatomical variations of the brachial plexus is important for examinations and interventions in the lower neck and axilla. The variability was observed especially in the roots forming trunks, while divisions forming cords showed quite stable appearance. The results of this evidence-based review and meta-analysis can be applied in many different medical disciplines.
臂丛是一个复杂的解剖结构，它为上肢的所有神经提供了起源。它的变异性经常被观察到，这对颈部和腋窝下部的干预措施构成了挑战。本研究的目的是用荟萃分析技术对臂丛神经根、干、分支和束的变异性进行全面的、基于证据的综述。
主要医学数据库被检索以确定所有研究臂丛形成变异的解剖学研究。提取的数据包括人口统计学信息、形态测量参数、臂丛在神经根、干、分支和束水平的排列以及臂丛与腋动脉和斜角肌的关系。臂丛的不同结构被归入一个新的分类，并使用随机效应模型计算每种情况的合并患病率。还进行了年龄和地理位置的亚分析。
共有 40 项研究（3055 例上肢）纳入荟萃分析。84%（95%置信区间 79-89%）的病例中形成干的神经根呈规则排列。前置和后置臂丛的总患病率分别为 11%（95%置信区间 6-17%）和 1%（95%置信区间 0-1%），而不到 0.1%的病例中臂丛从 C4 和 T2 都接受了分支。对于形成束的分支，96%（95%置信区间 93-98%）的病例中观察到规则排列。臂丛各成分之间出现额外的沟通分支的比例为 5%（95%置信区间 3-7%）。臂丛与腋动脉和斜角肌的关系分别被认为在 96%（95%置信区间 89-100%）和 86%（95%置信区间 66-98%）的病例中是规则的。形态测量参数的分析表明，在老化过程中，形成丛的各成分之间存在比例一致性。
了解臂丛的解剖变异对颈部和腋窝下部的检查和干预很重要。这种变异性主要发生在形成干的神经根中，而形成束的分支则表现出相当稳定的外观。本基于证据的综述和荟萃分析的结果可应用于许多不同的医学学科。
