1. (A) Left interscalene brachial plexus
(A) Left interscalene brachial plexus. A portion of the flattened hypoechoic sternocleidomastoid (SCM) muscle is seen in the left near field. The three vertically oriented hypoechoic circles in the center of the sonogram represent the C5, C6, and C7 nerve roots (above arrow). They are typically arranged in a vertical pattern known as the “traffic light sign,” are surrounded by a rim of hyperechoic fascia, and are located in the interscalene groove located between the anterior and middle scalene muscles. (B) Right interscalene brachial plexus. A portion of the hypoechoic SCM muscle is now seen in the right near field. The plexus (C5, C6, C7) is seen in the interscalene groove, surrounded by echogenic fascia, located between the anterior scalene (AS) and middle scalene (MS) muscles. (C) Left interscalene brachial plexus block. Anechoic local anesthetic solution (asterisks) is visualized in the interscalene groove adjacent to the C5, C6, and C7 nerve roots. The SCM muscle lies superficially, and the AS and middle scalene (MS) muscles define the medial and lateral borders, respectively, of the interscalene groove.
Source: Chapter 22. Additional Ultrasound-Guided Procedures, Ma and Mateer's Emergency Ultrasound, 3e
Citation: Ma O, Mateer JR, Reardon RF, Joing SA. Ma and Mateer's Emergency Ultrasound, 3e; 2014 Available at: Accessed: January 01, 2018
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