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Objective: To describe the pattern and prevalence of variations that occur in the supraclavicular part of the brachial plexus in a
Kenyan population.
Study design: Descriptive cross-sectional study.
Materials and methods: Ninety-four brachial plexuses from forty-seven formalin fixed cadavers were displayed by gross
dissection.
Results: The presence...
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Citations
... The data on the anatomy of the long thoracic nerve were extracted from a total of fifteen studies (835 upper limbs) (Ballesteros and Ramirez, 2007;Bertelli and Ghizoni, 2005;Emamhadi et al., 2016;Erdogmus and Govsa, 2004;Fazan et al., 2003;Horwitz and Tocantis, 1938;Kirik et al., 2018;Lee et al., 1992;Matejcik, 2003;Olabu et al., 2008;Seema and Gangadhar, 2015;Sinha et al., 2012;Tubbs et al., 2006;Wang et al., 2008;Yazar et al., 2009). The usual origin from the C5, C6 and C7 roots (type A) was observed in 78.1% (95% CI 69.4-86.7%) of cases, while the rest (21.9%; 95% CI 13.3-30.6%) ...
... A total of eleven studies (620 upper limbs) contained information on the origin of the dorsal scapular nerve (Ballesteros and Ramirez, 2007;Fazan et al., 2003;Jack et al., 2020;Kirik et al., 2018;Lee et al., 1992;Matejcik, 2003;Nguyen et al., 2016;Olabu et al., 2008;Sharma et al., 2020;Sinha et al., 2012;Tubbs et al., 2005). The typical site of origin from the C5 root (type A) was observed in 85.2% (95% CI 75.7-94.6%) ...
... The origin of the suprascapular nerve was discussed in fourteen studies (893 upper limbs) (Ajmani, 1994;Aktan et al., 2001;Al-Hubaity et al., 2005;Arad et al., 2014;Ballesteros and Ramirez, 2007;Emamhadi et al., 2016;Fazan et al., 2003;Kirik et al., 2018;Lee et al., 1992;Leung et al., 2015;Matejcik, 2003;Metwally et al., 2016;Olabu et al., 2008;Sinha et al., 2012). In 89.8% (95% CI 85.1-94.4%), the usual origin from the superior trunk (type A) was identified, while in 10.2% (95% CI 5.6-14.9%) of cases the nerve expressed variability in its origin (types B-G). ...
Introduction:
The anatomy of the supraclavicular part of the brachial plexus is highly variable, therefore the aim of this study was to perform a systematic review and meta-analysis of the various origins of the long thoracic, dorsal scapular, suprascapular and subclavian nerves.
Materials and methods:
Major electronic databases were searched to identify all cadaveric studies investigating the morphology of the supraclavicular part of the brachial plexus. Data on the origins of these nerves were extracted and classified. A random effects meta-analysis was performed to state the pooled prevalence estimates.
Results:
A total of 26 studies, constituting a total of 1 021 cases, were deemed eligible for inclusion into the meta-analysis. The usual origin of the long thoracic nerve from the C5, C6 and C7 roots was observed in 78.1% (95% CI 69.4-86.7%) of cases and 21.9% (95% CI 13.3-30.6%) had unusual origin. An accessory long thoracic nerve occurred in 0.3% (95% CI 0-0.7%) of cases. The overall prevalence of normal site of origin from the C5 root of the dorsal scapular nerve was found in 85.2% (95% CI 75.7-94.6%) of cases, while 14.8% (95% CI 5.4-24.3%) appeared abnormal. The suprascapular nerve emerged from its usual point on the superior trunk in 89.8% (95% CI 85.1-94.4%) of cases and in 10.2% (95% CI 5.6-14.9%) of cases had a variable origin. An accessory suprascapular nerve was present in 0.2% (95% CI 0-0.6%). Two possible sites of origin of the subclavian nerve were noted and the typical origin from the superior trunk was found in 98.3% (95% CI 96.3-100%) of cases and variable origin from the C5 root in 1.7% (95% CI 0-3.7%). All unusual origins of each nerve were much less common.
Conclusions:
The nerves emerging from the supraclavicular part of the brachial plexus express a wide spectrum of potential origins. Based on the various points of emergence, a new classification system for all the nerves belonging to the supraclavicular part was proposed. Knowledge of these variations and their prevalence data is important to prevent iatrogenic injuries and to state useful landmarks for interventions in the axilla.
... A total of 31 studies (n = 2286 upper limbs) contained information on roots forming trunks (Adebisi and Singh, 2002;Akboru et al., 2010;Al-Hubaity et al., 2005;Andrade and Singh, 2019;Aragao et al., 2014;Bonnel, 1984;Chaudhary et al., 2014;Chetrick and Del Guercio, 1951;Emamhadi et al., 2016;Fazan et al., 2003;Guday et al., 2017;Khan et al., 2014Khan et al., , 2016Kirik et al., 2018;Lee et al., 1992;Manna et al., 2017;Matejcik, 2003;Olabu et al., 2008;Oliveira-Filho et al., 2009;Pattanshetti et al., 2012;Prasad and Patel, 2016;Priya et al., 2018;Rastogi et al., 2013;Sharma et al., 2020;Shetty et al., 2011;Singh, 2017;Singh et al., 2019;Sinha et al., 2012;Uysal et al., 2003;Uzun and Bilgic, 1999;Wozniak et al., 2012). The number and pooled prevalence of each variation in each study is shown in Table 2 as well as in the Fig. 1. ...
... Ten studies (n = 855 upper limbs) contained data on the relationship between the parts of the brachial plexus and the scalene muscles (Akboru et al., 2010;Guday et al., 2017;Harry et al., 1997;Keet and Louw, 2019;Leonhard et al., 2016;Matejcik, 2003;Olabu et al., 2008;Shetty et al., 2011;Tokat et al., 2011;Uysal et al., 2003). The typical layout where the roots or trunks pass through the interscalene gap was present in 660 cases (86%; 95% CI 66-98%). ...
Introduction:
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.
Materials and methods:
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.
Results:
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.
Conclusions:
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.
The dorsal scapular nerve (DSN) entrapment neuropathy has recently been recognized as a common cause of circumscapular pain and cases of winged scapula. Course of the nerve is important because the middle scalene muscle is frequently accessed for surgical treatments. Studies in the literature have not focused on the morphometric relationship of the DSN with the scalene muscles and its relationship with the long thoracic nerve (LTN). The neck regions of 13 adult cadavers were dissected bilaterally. The relationship of DSN with scalene muscles and LTN was evaluated. Cervical spinal nerves involved in the formation of the DSN were identified. Three types of DSN were observed based on the cervical spinal nerves from which it originates, five types of DSN from its relationship with the scalene muscles, and two types of DSN from its relationship with the LTN. The distance from where the nerve pierces the scalene muscle to the mastoid process was found to be greater in DSNs originating from C4 and C5 (93.85 ± 4.11 mm, p = 0.033). In DSNs not connected with LTN, the distance from where the nerve pierces the scalene muscle to the superior trunk/C5 (12.74 ± 7.73 mm, p = 0.008) and the length of the nerve within the scalene muscle (14.94 ± 5.5 mm, p = 0.029) were found to be statistically significantly greater. The topographic and morphometric anatomy of the proximal part of the DSN is important, especially for scalene muscles‐focused surgical treatments and interscalene nerve blocks. We believe our results may guide clinical approaches and surgery.
Purpose of review:
The brachial plexus is an important anatomical structure that is regularly encountered by head and neck surgeons and radiation oncologists. Surgical or radiation-induced brachial plexus injury have great impact on arm function and quality of life. Anatomical variations and management of the brachial plexus in head and neck cancer treatment are discussed.
Recent findings:
The brachial plexus consists of spinal roots from C5-C8 and T1. The most prevalent anatomical variations in brachial plexus anatomy include the prefixed brachial plexus (additional contribution from C4) in 11%, the roots of C5 and C6 piercing the belly of the anterior scalene muscle in 6.8%, and presence of the scalenus minimus muscle in 4.1-46%. Due to its location, the brachial plexus is at risk of inadvertent division or neuropraxia during surgical procedures such as neck dissection or robot-assisted transaxillary thyroid surgery (RATS). In case of inadvertent division, nerve reconstruction surgery is warranted and may lead to improved function. The risk of radiation-induced brachial plexus injury is dose-dependent and occurs in approximately 12-22%. Currently, no successful treatment options exist for radiation-induced injury.
Summary:
Knowledge of anatomical variations is important for head and neck surgeons to minimize the risk of brachial plexus injury. Limiting radiation therapy dose to the brachial plexus is desirable to decrease the risk of brachial plexus injury.
