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Pleura

Q: What pleural recesses exist?

Costodiaphragmatic recess (recessus costodiaphragmaticus) — the largest and deepest recess, forming a semicircle from the cartilage of the 6th rib to the vertebral column, where it descends below the 12th rib posteriorly.Mediastinodiaphragmatic recess (recessus mediastinodiaphragmaticus) — formed at the transition of the mediastinal pleura into the diaphragmatic pleura; significantly smaller than the costodiaphragmatic recess.Anterior costomediastinal recess (recessus costomediastinalis anterior) — formed at the anterior transition of the costal pleura into the mediastinal pleura; more prominent on the left due to the cardiac notch of the lung.Posterior costomediastinal recess (recessus costomediastinalis posterior) — formed at the posterior transition of the costal pleura into the mediastinal pleura.

Q: At the level of which ribs does the inferior border of the parietal pleura pass along the main topographic lines?

Midclavicular line (linea medioclavicularis) — 7th rib.Midaxillary line (linea axillaris media) — 10th rib.Scapular line (linea scapularis) — 11th rib.Paravertebral line (linea paravertebralis) — 12th rib.

Q: At what level is the cervical pleura (cupula) located relative to the clavicle and the first rib?

The cervical pleura (cupula pleurae) projects above the clavicle into the neck by 2–3 cm, corresponding to 3–4 cm above the 1st rib, and posteriorly corresponds to the spinous process of the 7th cervical vertebra.

Q: Which pleural recess is the deepest and why is it important?

The deepest recess is the costodiaphragmatic recess (recessus costodiaphragmaticus). Pathological fluid (blood, exudate) accumulates here first during diseases or trauma.

For medical students2 min readUpdated 2026-10-10

The pleura (pleura) is a serous membrane forming a closed sac around each lung. It consists of two continuous layers that transition into one another, creating a potential space for the safe movement of the lungs within the thoracic cavity.

Pleural layersVisceral (on the lung) and parietal (lining the thoracic walls).

Pleural cavityContains a small amount of serous fluid.

Deepest recessCostodiaphragmatic recess (*recessus costodiaphragmaticus*).

Left borderDeviates laterally due to the adjacent heart.

Visceral Pleura

The visceral pleura (pleura visceralis) is the inner layer of the serous membrane that directly covers the lung itself.

A key feature of this layer is that it is tightly fused to the pulmonary surface. It is virtually impossible to separate surgically or on an anatomical specimen without damaging the lung tissue. Furthermore, the visceral pleura not only covers the outer surface of the lung but also extends deeply into the interlobar fissures, completely lining the facing surfaces of the lung lobes.

Parietal Pleura and its Parts

The parietal pleura (pleura parietalis) is the outer layer lining the inner walls of the thoracic cavity. Topographically, the parietal pleura is subdivided into four parts based on the thoracic structures it contacts:

Pleura costalis (costal pleura) — lines the internal surface of the ribs and intercostal spaces.
Pleura diaphragmatica (diaphragmatic pleura) — covers the superior surface of the diaphragm.
Pleura mediastinalis (mediastinal pleura) — bounds the mediastinum laterally.
Cupula pleurae (cervical pleura / pleural cupula) — the apex of the parietal layer projecting above the superior thoracic aperture.

Pleural Cavity

Between the inner (visceral) and outer (parietal) layers lies a closed, slit-like potential space called the pleural cavity (cavitas pleuralis).

Normally, this cavity contains no air and is filled only with a small amount of serous fluid. This fluid acts as a lubricant, reducing friction between the layers during respiratory movements (inspiration and expiration) and maintaining surface tension that keeps the lung surfaces apposed to the thoracic wall.

Pleural Recesses

Where one part of the parietal pleura transitions into another (e.g., costal into diaphragmatic), deep recesses of the pleural cavity are formed, known as pleural recesses (recessus pleurales). These serve as reserve spaces that the lungs enter only during deep inspiration.

The main recesses include:

Recessus costodiaphragmaticus (costodiaphragmatic recess) — formed at the junction of the costal and diaphragmatic pleura. It is the deepest pocket of the pleural cavity.
Recessus costomediastinalis (costomediastinal recess) — located at the transition of the costal pleura into the mediastinal pleura.

Anterior Border of the Parietal Pleura

The topography of the anterior border of the parietal layer is clinically significant and differs on the right and left sides.

The course of the anterior border is defined by the following landmarks:

Begins superiorly at the level of the sternoclavicular joint.
Descends along the margin of the sternum.
On the right, the border goes straight down and reaches the level of the 6th rib.
On the left, the border does not descend strictly vertically: at the level of the lower rib cartilages, it makes a marked curve and deviates laterally. This asymmetry is due to the position of the heart, which displaces the left pleural sac.

Mnemonic

To easily remember the parts of the parietal pleura, picture the thoracic cavity as a room: the cupula (cupula pleurae) is the ceiling, the costal pleura (pleura costalis) is the outer walls, the diaphragmatic pleura (pleura diaphragmatica) is the floor, and the mediastinal pleura (pleura mediastinalis) is the inner partition wall.

Frequently asked questions

What pleural recesses exist?

Costodiaphragmatic recess (recessus costodiaphragmaticus) — the largest and deepest recess, forming a semicircle from the cartilage of the 6th rib to the vertebral column, where it descends below the 12th rib posteriorly.
Mediastinodiaphragmatic recess (recessus mediastinodiaphragmaticus) — formed at the transition of the mediastinal pleura into the diaphragmatic pleura; significantly smaller than the costodiaphragmatic recess.
Anterior costomediastinal recess (recessus costomediastinalis anterior) — formed at the anterior transition of the costal pleura into the mediastinal pleura; more prominent on the left due to the cardiac notch of the lung.
Posterior costomediastinal recess (recessus costomediastinalis posterior) — formed at the posterior transition of the costal pleura into the mediastinal pleura.

At the level of which ribs does the inferior border of the parietal pleura pass along the main topographic lines?

Midclavicular line (linea medioclavicularis) — 7th rib.
Midaxillary line (linea axillaris media) — 10th rib.
Scapular line (linea scapularis) — 11th rib.
Paravertebral line (linea paravertebralis) — 12th rib.

How does the posterior border of the parietal pleura run?

The posterior border of the parietal pleura corresponds to the costovertebral joints.

Which nerves innervate the parietal and visceral pleura?

Afferent fibers from the visceral pleura travel via the vagus nerve, whereas those from the parietal pleura travel via the intercostal nerves and the phrenic nerve (n. phrenicus).

At what level is the cervical pleura (cupula) located relative to the clavicle and the first rib?

The cervical pleura (cupula pleurae) projects above the clavicle into the neck by 2–3 cm, corresponding to 3–4 cm above the 1st rib, and posteriorly corresponds to the spinous process of the 7th cervical vertebra.

What is the main anatomical difference between the visceral and parietal pleura?

The visceral pleura is tightly fused to the lung tissue and extends into its interlobar fissures, whereas the parietal pleura lines the thoracic walls and can be easily separated from them.

What is inside the cavitas pleuralis?

Normally, the pleural cavity contains only a small amount of serous fluid, which is necessary to minimize friction between the layers during breathing.

Which pleural recess is the deepest and why is it important?

The deepest recess is the costodiaphragmatic recess (recessus costodiaphragmaticus). Pathological fluid (blood, exudate) accumulates here first during diseases or trauma.

Why is the anterior border of the left pleura asymmetric to the right?

On the left, the anterior border of the parietal pleura deviates laterally to accommodate the heart, which is shifted to the left side of the thoracic cavity.

Go deeper

Detailed projection of the cervical pleura relative to the clavicle and 1st rib
Topography and borders of the costomediastinal recess on the skeletal framework
Course of the posterior and inferior borders of the parietal pleura
Anatomical relationships of the visceral pleura at the root of the lung
Clinical significance of pleural recesses during thoracentesis