The anatomy of the pectoral nerves and its significance in breast augmentation, axillary dissection and pectoral muscle flaps.

Background: In many plastic surgeries, a detailed understanding of the pectoral nerve anatomy is often required. However, the information available on the anatomy of pectoral nerves is sparse and unclear. The purpose of this study is to provide detailed anatomical information on the pectoral nerves to allow for their easy intra-operative localisation and to improve the understanding of the pectoral muscle innervation.

Methods: We dissected 26 brachial plexuses from 15 fresh cadavers. The origins, locations, courses and branches of the pectoral nerves were recorded.

Results: We found three constant branches of the pectoral nerve. The superior branch travelled in a straight course to the pectoralis major to innervate the clavicular aspect. The middle branch coursed on the under-surface of the pectoralis major near the pectoral branch of the thoraco-acromial artery to innervate the muscle's sternal aspect. The inferior branch passed beneath the pectoralis minor muscle to innervate the pectoralis minor muscle and the costal aspect of the pectoralis major muscle.

Conclusions: Knowing the pectoral nerves' origins, courses and connections, in addition to understanding the functional consequences of iatrogenically severing these nerves, leads to a better understanding of the pectoral muscle's innervation. Precise anatomical data on the pectoral nerve allow for its easy localisation during axillary breast augmentation, axillary dissection, removal of the pectoralis minor muscle and harvesting the pectoralis major muscle island flap.