At the level of the first rib, the lower cervical nerve roots ... that make up the ulnar nerve is uncommon. The ulnar nerve may also be trapped as it passes into the hand through Guyon's canal.

In other words, the first rib, moved down toward the thoracic space, enhances the visualization of the cervical bands of the nerve, artery, and scalenus muscles. Consequentlyendolysis of the bands ...

"In the first study, we found a way to avoid injury to the intercostal nerve that lies below the sixth rib during closure by drilling holes in the ribs so the closure stitches would not entrap ...