Where should the electrode be placed to record the cervical cord response to median nerve stimulation?

To accurately record the cervical cord response to median nerve stimulation, the electrode should be placed at C5. This position is crucial because it allows for optimal measurement of the somatosensory evoked potentials (SSEPs) generated by the sensory input from the median nerve, which travels through the brachial plexus and enters the spinal cord at cervical levels such as C5.

C5 is significant as it lies within the appropriate cervical region that processes upper limb sensory information, including the pathways involved with the median nerve. Electrode placements at other cervical levels, such as C1, C2, or even C8, would not capture the desired cervical cord response effectively due to anatomical and functional considerations. C1 and C2 are too high in the cervical spine, while C8 is lower and primarily responsible for sensory information from the lower part of the arm, missing the response relevant to the stimulation from the median nerve. Thus, C5 is the ideal choice for capturing the cervical cord response accurately.