Intercostal nerves are a set of nerves in the body that are part of the brachial plexus. They are located between the ribs and are included in various structures of the body such as the spine, chest and shoulder girdle. The intercostal nerves can be divided into subgroups depending on their location and functions.
The intercostal portion of nerve A lies along the ribs and enters the side of the chest and then into the anterior part of the shoulder. It can be used to control the muscles of the chest and diaphragm.