Anatomical variations in the brachial plexus roots: implications for diagnosis of neurogenic thoracic outlet syndrome

详细信息    查看全文

• 作者：Vanessa Leonhard^a ; Riley Smith^a ; Gregory Caldwell^a ; Heather F. Smith^b ; ^c ; ^{hsmith@midwestern.edu" class="auth_mail" title="E-mail the corresponding author} ; ^{heather.f.smith@asu.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Anatomical variation ; Brachial plexus ; Superior trunk ; Middle trunk ; Anterior scalene muscle ; Neurogenic thoracic outlet syndrome
• 刊名：Annals of Anatomy - Anatomischer Anzeiger
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：206
• 期：Complete
• 页码：21-26
• 全文大小：1149 K

文摘

Neurogenic thoracic outlet syndrome (NTOS) is the most common type of TOS. Typically it results from impingement of the neurovasculature as it passes between the anterior and middle scalene muscles; this classic anatomical relationship being the foundation of clinical diagnosis. Positional testing relies on vascular compromise occurring when the subclavian artery is compressed in this space. This study describes several anatomical variations observed in this relationship.

Sixty-five cadavers (35m/30f) were assessed to determine the frequency and extent of brachial plexus branching variants. A total of thirty-one variations from “classic” anatomy were observed (47.7%). In two specimens (3.1%), the entire superior trunk coursed completely anterior to the anterior scalene in a position of relative vulnerability. In 27 instances, a portion of or the entire superior trunk pierced the anterior scalene muscle, and in two, the middle trunk also pierced the muscle belly. Interestingly, while two bilateral branching variations were observed, the majority occurred unilaterally, and almost exclusively on the left side. There were no sex differences in frequency.

The high frequency of these variations and their potential to predispose patients to neurogenic TOS suggest that current diagnostic methods may be insufficient in clinical diagnosis. Due to lack of vascular compromise, patients with the piercing variant would not display positive signs on the traditional positional tests. The use of ultrasound to determine the route of the brachial plexus could determine whether this variation is present in patients who suffer from TOS symptoms but lack a diagnosis based on traditional positional testing.