Lateral cutaneous branch of intercostal nerve

Lateral pectoral cutaneous branches (rami cutanei laterales) are derived from the upper intercostal nerves (2 to 6), about midway between the vertebræ and sternum; they pierce the Intercostales externi and Serratus anterior, and divide into anterior and posterior branches.

• The anterior branches run forward to the side and the forepart of the chest, supplying the skin and the mamma (Lateral mammary branches); those of the fifth and sixth nerves supply the upper digitations of the Obliquus externus abdominis.
• The posterior branches run backward, and supply the skin over the scapula and Latissimus dorsi