What is a double crush syndrome? If there is irritation of a nerve root in the neck, as that nerve passes into the arm, it passes through several muscles and joints before it enters the hand. If the already irritated nerve then has a “secondary stress”, there may be regional symptoms at that location. That second area pressure on the nerve is the “double crush” phenomenon. Chiropractic adjustments can help reduce primary and secondary nerve irritation. This is also true of entrapment syndromes developed from associated muscle adhesions and “trigger points”.