Nerve · Chest

Medial pectoral nerve

Nervus pectoralis medialis

The smaller and lower of the two nerves to the chest muscles, arising from the medial cord of the brachial plexus and carrying the lowest segments of the plexus, C8 and T1. It passes forward between the axillary artery and vein, then does something no other nerve in the axilla does: it enters pectoralis minor, supplies it, and drives straight on through the muscle to reach the lower fibres of pectoralis major beyond it. Because it is the only nerve to both chest muscles, its short course pins pectoralis minor to the neurovascular bundle behind it — the reason that small muscle is described as a landmark for the axillary vessels.