Medial pectoral nerve

The medial pectoral nerve originates from the medial cord of the brachial plexus, with its "medial" designation reflecting this origin. It typically contains fibers from the spinal nerve roots C8 and T1.

The nerve travels through or around the lower border of the pectoralis minor muscle to reach the pectoralis major muscle, providing motor innervation to the pectoralis minor and the lower portions of the pectoralis major.

Conversely, the lateral pectoral nerve arises from the lateral cord of the brachial plexus, with its "lateral" designation corresponding to its origin. It typically contains fibers from the spinal nerve roots C5, C6, and C7, and innervates the upper portions of the pectoralis major muscle.

Communication between the lateral and medial pectoral nerves via an anastomosis, known as the "ansa pectoralis," may also contribute to the innervation of the pectoral muscles.