Final answer:
The medial and lateral pectoral nerves, originating from the brachial plexus, collectively innervate the pectoralis major muscle. The lateral pectoral nerve supplies the clavicular head while the medial pectoral nerve innervates the sternocostal head of the pectoralis major.
Step-by-step explanation:
Nerve Distributing the Deep Medial Surface of the Pectoralis Major
The nerve that innervates the deep medial surface of the pectoralis major muscle is not explicitly mentioned in the provided materials. However, the general innervation of the pectoralis major is typically by the medial and lateral pectoral nerves, which arise from the brachial plexus. The lateral pectoral nerve predominantly supplies the clavicular head of the pectoralis major, while the medial pectoral nerve passes through the pectoralis minor to innervate the sternocostal head of the pectoralis major.
While the exact nerve the student is inquiring about, specifically the one distributing to the deep medial surface of the pectoralis major, is not identifiable from the given information, understanding the overall innervation helps in deducing that the medial pectoral nerve likely contributes to this area along with the lateral pectoral nerve given their collective role in innervating the pectoralis major.