Parietal pleura

Pleura parietalis

Also known as: costal pleura, mediastinal pleura, diaphragmatic pleura, cervical pleura, cupula

The outer pleural layer lining the thoracic wall, diaphragm and mediastinum; supplied by somatic nerves and therefore exquisitely sensitive to pain.

Overview

The parietal pleura is named by the surface it lines: costal (inner surface of ribs, costal cartilages and intercostal spaces, separated from them by endothoracic fascia), mediastinal (lateral surfaces of the mediastinum, continuous with the visceral pleura at the root), diaphragmatic (upper surface of the diaphragm) and cervical (the cupula, rising 2–3 cm above the medial third of the clavicle into the neck, reinforced by the suprapleural membrane — Sibson's fascia).

It produces most pleural fluid by filtration from its systemic capillaries and reabsorbs it through lymphatic stomata, chiefly in the diaphragmatic and mediastinal pleura. Its somatic innervation means that irritation causes sharp, well-localised (or referred) pain.

Location

Lining the pulmonary cavities of the thorax.

Parts & subdivisions

Costal pleura

Lines the ribs and intercostal spaces; intercostal nerves.

Mediastinal pleura

Covers the mediastinum; phrenic nerve.

Diaphragmatic pleura

Central part — phrenic nerve; peripheral part — lower intercostal nerves.

Cervical pleura (cupula)

Projects into the root of the neck above the first rib; intercostal nerves.

Anatomy

Innervation

Costal and peripheral diaphragmatic pleura: intercostal nerves (pain felt over the chest wall or referred to the anterior abdominal wall). Mediastinal and central diaphragmatic pleura: phrenic nerve (C3–C5; pain referred to the root of the neck and tip of the shoulder).

Arterial supply

Systemic arteries of the thoracic wall: intercostal, internal thoracic, musculophrenic and superior phrenic arteries.

Venous drainage

Systemic veins of the thoracic wall (intercostal and internal thoracic veins).

Lymphatic drainage

Parasternal, intercostal, posterior mediastinal and diaphragmatic nodes.

Clinical significance

Referred pleural pain

Lower costal pleuritis (e.g. lower-lobe pneumonia) can present as abdominal pain via the lower intercostal nerves; central diaphragmatic pleural irritation causes shoulder-tip pain via the phrenic nerve.

Cupula injury

Because the cupula lies above the clavicle, subclavian/internal jugular line insertion, supraclavicular brachial plexus block or a penetrating neck wound can puncture it and cause a pneumothorax.

Mesothelioma

Malignant mesothelioma of the pleura is strongly associated with asbestos exposure (latency 20–40 years); presents with chest pain and recurrent effusion, and encases the lung.