Which spinal roots contribute to the phrenic nerve function?

The phrenic nerve is crucial for diaphragmatic function and is primarily responsible for motor innervation to the diaphragm, which is essential for respiration. The correct spinal roots that contribute to the phrenic nerve are derived from the cervical region, specifically C3, C4, and C5.

These cervical nerves combine to form the phrenic nerve, with the majority of its fibers originating from C4. The mnemonic "C3, C4, C5 keeps the diaphragm alive" is often used to remember this important anatomical relationship. If there is injury to these spinal roots, it can lead to diaphragmatic paralysis and significant respiratory distress, demonstrating the vital role this nerve plays in breathing. The other options listed do not contribute to the phrenic nerve function, as they originate from different regions of the spinal cord that are not involved in the innervation of the diaphragm.