Nerve Supply and Blood Supply of the Pleura
Nerve Supply
Parietal Pleura — Somatic Innervation
Parietal pleura develops from somatopleuric mesoderm → supplied by somatic nerves → sensitive to pain.
| Region of Parietal Pleura | Nerve Supply |
|---|---|
| Costal pleura | Intercostal nerves (T1–T11) |
| Peripheral part of diaphragmatic pleura | Intercostal nerves |
| Mediastinal pleura | Phrenic nerve (C3, C4, C5) |
| Central part of diaphragmatic pleura | Phrenic nerve (C3, C4, C5) |
| Cervical pleura | Intercostal nerves (lower cervical/upper thoracic) |
Visceral Pleura — Autonomic Innervation
Visceral pleura develops from splanchnopleuric mesoderm → supplied by autonomic nerves → insensitive to pain.
| Component | Nerve |
|---|---|
| Sympathetic | T2–T5 ganglia (via bronchial vessels) |
| Parasympathetic | Vagus nerve |
Sympathetic stimulation → dilates bronchi; Parasympathetic → constricts bronchi and stimulates secretion
Referred Pain from the Pleura
Because pain from the parietal pleura is referred along the nerve that supplies it:
| Pleural Region Irritated | Via Nerve | Referred Pain Site |
|---|---|---|
| Costal pleura + peripheral diaphragmatic pleura | Intercostal nerves (T1–T11) | Thoracic wall and abdominal wall (along intercostal distribution) |
| Mediastinal pleura + central diaphragmatic pleura | Phrenic nerve (C3, C4, C5) | Tip of the shoulder (supraclavicular nerves C3, C4, C5 supply the same skin) |
Clinical Examples
- Right shoulder pain → irritation of right central diaphragmatic pleura (e.g., right-sided pneumonia, subphrenic abscess, acute cholecystitis/gallbladder disease)
- Left shoulder pain → irritation of left central diaphragmatic pleura (e.g., splenic rupture, left-sided pneumonia)
- Abdominal wall pain → irritation of lower costal pleura (can mimic acute abdomen — e.g., lower lobe pneumonia presenting with abdominal pain)
Blood Supply
Parietal Pleura
Blood supply follows that of the thoracic wall:
- Intercostal arteries
- Internal thoracic (mammary) artery
- Musculophrenic artery (for diaphragmatic pleura)
- Pericardiacophrenic artery (for mediastinal pleura — runs with the phrenic nerve)
Venous drainage: Azygos vein and internal thoracic veins
Visceral Pleura
Blood supply follows that of the lung:
- Bronchial arteries (supply the airway and connective tissue of the lung)
Venous drainage: Bronchial veins (drain into azygos system) — though much of the bronchial venous blood drains into the pulmonary veins
Lymphatic Drainage
| Layer | Drains to |
|---|---|
| Parietal pleura | Intercostal lymph nodes, internal mammary (parasternal) nodes, posterior mediastinal nodes, diaphragmatic nodes |
| Visceral pleura | Tracheobronchial lymph nodes (via bronchopulmonary nodes at the hilum) |