innervation
Last reviewed 01/2018
Pectoralis major is supplied by fibres from all segments of the brachial plexus and hence pectoralis major function may be an index of brachial plexus damage. The individual nerves are:
- medial pectoral nerve (C8, T1), so titled because of its origin from the medial cord of the plexus
- lateral pectoral nerve (C5, C6, C7), from the lateral cord of the plexus
The clavicular part of the muscle is largely supplied by C5 and C6. The sternocostal part is innervated by C7, C8 and T1.
The afferent supply from the skin overlying pectoralis major passes to thoracic nerve roots T2 to T6.