The skin over the xiphoid process is innervated by the following thoracic spinal nerve

The skin over the xiphoid is innervated by the thoracic spinal nerve from T6. The anterior chest wall is innervated by the lateral cutaneous branches and anterior cutaneous branches of the intercostal nerves. Intercostal nerves T7 to T11 and the subcostal nerve T12 supply the skin and muscle of the abdominal wall. In addition, T5 and T6 supply the upper pas of the external oblique muscle of the abdominal wall. The highest thoracic dermatome on the anterior chest wall is T2. Ref: Gray's Anatomy 41st edition Pgno: 945