Anatomy: Ultrasound guided interscalene block is performed at the root/trunk level of the brachial plexus (approx. C6/7 vertebral level, corresponding to the cricoid cartilage level). At this level, the roots/trunks lie wedged between the scalene muscles (Fig.1).ig. 1. Interscalane nerve block: illustration of the roots/trunks at the C6/7 vertebral level lying in between the anterior and middle scalene muscles. At the immediate supraclavicular level, the trunks/divisions are closely grouped superolateral (and posterolateral) to the subclavian artery.
When a word like and, or, and but (called conjunctions) joins two standalone sentences, you should put a comma before it. (The real name for a standalone sentence within a longer sentence is independent clause .). Words like and, or, and but are known as conjunctions.
The short answer is no. Itâs unusual to put a comma before because. You only do it when you need the comma to prevent confusion because your sentence could have two meanings. The Chicago Manual of Style has an excellent entry on this topic in its Q&A section online. It gives the example.