Root value of intercostobrachial nerve is

The intercostobrachial nerve is a lateral cutaneous branch of the second intercostal nerve that supplies sensation to the skin of the Axilla . It leaves the second intercostal space at the midaxillary line and subsequently pierces the serratus anterior muscle to enter the subcutaneous tissues of the axilla. The nerve may be injured during axillary surgery such as nodal clearance for breast cancer The anterior divisions of the second, third, fouh, fifth, and sixth thoracic nerves, and the small branch from the first thoracic, are confined to the walls of the thorax, and are named thoracic intercostal nerves respectively . They pass forward in the intercostal spaces below the intercostal vessels. At the back of the chest they lie between the pleura and the posterior intercostal membranes, but soon they run between the internal intercostals and the innermost intercostals then anteriorly they lie between the pleura and the internal intercostals . Ref - radiology assistant.com