Definition

Noun: - The phrenic nerve: One of a pair of nerves that originates from the cervical spinal cord (specifically from spinal nerve roots C3, C4, and C5), descends through the thorax, and provides motor innervation to the diaphragm, the primary muscle responsible for breathing.

Usage

• The nervus phrenicus is critical for the autonomic control of respiration.
• Damage to the nervus phrenicus can result in paralysis of the diaphragm on the affected side.
• Surgeons must take care to avoid the nervus phrenicus during procedures in the neck and upper chest.

Advanced Usage

• Clinical Significance: The nervus phrenicus is a common target for nerve blocks to manage pain, such as hiccups (singultus) that are intractable to other treatments. It is also monitored during cardiac surgery to prevent iatrogenic injury.
• "Phrenic nerve pacing": A therapeutic application where the nervus phrenicus is electrically stimulated to induce diaphragmatic contraction in patients with respiratory insufficiency, such as those with high cervical spinal cord injuries.

Variants and Related Words

• Phrenic nerve: The common English term for . These terms are used interchangeably in medical contexts.
  • The phrenic nerve and the nervus phrenicus refer to the same anatomical structure.
• Phrenic (adj): Pertaining to the diaphragm or to the phrenic nerve.
  • Phrenic activity is essential for breathing.

Synonyms

• Phrenic nerve: The direct and most frequently used synonym.

Related Anatomical Terms (Not Synonyms)

• Diaphragm: The muscle innervated by the .
• Cervical plexus: The network of nerves in the neck from which the primarily arises (from the C3-C5 roots, often described as the "phrenic nerve plexus").

Noun

1. one of a pair of nerves that arises from cervical spinal roots and passes down the thorax to innervate the diaphragm and control breathing