Medial pectoral nerve
The medial pectoral nerve arises from the medial cord of the brachial plexus and through it from the eighth cervical and first thoracic roots.
It passes behind the first part of the axillary artery, curves forward between the axillary artery and vein, and unites in front of the artery with a filament from the lateral nerve.
It then enters the deep surface of the pectoralis minor muscle, where it divides into a number of branches, which supply the muscle.
Two or three branches pierce the muscle and end in the sternocostal head of the pectoralis major muscle. The medial pectoral nerve pierces both the pectoralis minor and the sternocostal head of the pectoralis major. The lateral pectoral nerve pierces only the clavicular head of the pectoralis major.
