The intermediate supraclavicular nerves arise from the common trunk of the supraclavicular nerve deep to platysma and the deep cervical fascia.  They traverse the clavicle, before terminating in the skin over the pectoralis major and deltoid muscles, reaching as far down as the level of the second rib.

Supply
The intermediate and lateral branches supply skin and fascia related to corresponding thirds of the clavicle and skin over the pectoralis major and deltoid muscles as far as the sternal angle and second rib.