Anatomy study note · Head and neck

Phrenic nerve

The nerve of the diaphragm, from C3, C4 and C5 — the only motor supply to the diaphragm, and sensory to the pericardium, mediastinal pleura and the central diaphragmatic pleura and peritoneum.

Key points

• C3, 4, 5; on scalenus anterior.
• Sole motor nerve to the diaphragm.
• In front of the lung root.
• Accessory phrenic in ~1/3.
• Phrenic: in the pleuropericardial membrane; diaphragm descended from C3–5.
• Ventral root: basal-lamina neurons. Dorsal root: neural-crest ganglion cells.
• Nerve: epineurium → perineurium (blood–nerve barrier) → endoneurium.
• Cut nerve: Wallerian degeneration; regrows 0.5–3 mm/day.

The full note in the atlas also covers

Course · Histology · Development · Clinical notes

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Written from

• Snell’s Clinical Anatomy by Regions, 10th ed., ch. 12, PDF pp. 1690–1691; ch. 5, PDF pp. 653–654
• Inderbir Singh’s Human Embryology, ch. 17, PDF pp. 318, 321, 323–325; ch. 14, PDF pp. 214, 222
• BRS Cell Biology & Histology, 7th ed., ch. 9, PDF pp. 163–166, 171–172

More from the head and neck

• Pineal body
• Piriform cortex
• Pituitary gland
• Platysma
• Pons
• Postcentral gyrus
• Posterior cerebral artery
• Posterior cricoarytenoid
• Precentral gyrus
• Retina
• Salpingopharyngeus
• Scalenus anterior

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