The phrenic nerve is associated with which plexus?

The phrenic nerve is associated with which plexus?

• A. Brachial plexus
• B. Lumbar plexus
• C. Cervical plexus
• D. Sacral plexus

Answer: (C)

The phrenic nerve is formed from nerve fibers that originate in the cervical region—primarily from C3 to C5—which come together to make the nerves of the cervical plexus in the neck. Since the phrenic nerve carries those cervical roots down to the diaphragm, its association is with the cervical plexus. The other plexuses—brachial for the upper limb, and lumbar/sacral for the lower limbs and pelvis—do not give rise to the phrenic nerve. The diaphragm’s main motor supply comes from the phrenic nerve, so understanding its cervical origin helps explain its neck-to-diaphragm course.

The phrenic nerve is formed from nerve fibers that originate in the cervical region—primarily from C3 to C5—which come together to make the nerves of the cervical plexus in the neck. Since the phrenic nerve carries those cervical roots down to the diaphragm, its association is with the cervical plexus. The other plexuses—brachial for the upper limb, and lumbar/sacral for the lower limbs and pelvis—do not give rise to the phrenic nerve. The diaphragm’s main motor supply comes from the phrenic nerve, so understanding its cervical origin helps explain its neck-to-diaphragm course.