The intercostal space (ICS) is the anatomic space between two ribs (Lat. costa). Since there are 12 ribs on each side, there are 11 intercostal spaces, each numbered for the rib superior to it.

Structures in intercostal space

* several kinds of intercostal muscle *

intercostal arteries The intercostal arteries are a group of arteries that supply the area between the ribs ("costae"), called the intercostal space. The highest intercostal artery (supreme intercostal artery or superior intercostal artery) is an artery in the human ...

and

intercostal veins The intercostal veins are a group of veins which drain the area between the ribs ("costae"), called the intercostal space. They can be divided as follows: * Anterior intercostal veins * Posterior intercostal veins ** Posterior intercost vein that ...

* intercostal lymph nodes *

intercostal nerves The intercostal nerves are part of the somatic nervous system, and arise from the anterior rami of the thoracic spinal nerves from T1 to T11. The intercostal nerves are distributed chiefly to the thoracic pleura and abdominal peritoneum, and diffe ...

Order of components

Muscles

There are 3 muscular layers in each intercostal space, consisting of the external intercostal muscle, the internal intercostal muscle, and the thinner

innermost intercostal muscle The innermost intercostal muscle is a layer of intercostal muscles. It may also be called the intima of the internal intercostal muscles. It is the deepest muscular layer of the thorax, with muscle fibres running vertically (in parallel with the ...

. These muscles help to move the ribs during

breathing Breathing (or ventilation) is the process of moving air into and from the lungs to facilitate gas exchange with the internal environment, mostly to flush out carbon dioxide and bring in oxygen. All aerobic creatures need oxygen for cellular ...

Neurovascular bundles

Neurovascular bundles are located between the internal intercostal muscle and the innermost intercostal muscle. The

neurovascular bundle A neurovascular bundle is a structure that binds nerves and veins (and in some cases arteries and lymphatics) with connective tissue so that they travel in tandem through the body. Structure There are two types of neurovascular bundles: superficial ...

has a strict order of

vein Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenate ...

artery An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...

nerve A nerve is an enclosed, cable-like bundle of nerve fibers (called axons) in the peripheral nervous system. A nerve transmits electrical impulses. It is the basic unit of the peripheral nervous system. A nerve provides a common pathway for the ...

(VAN), from top to bottom. This neurovascular bundle runs high in the intercostal space, and the smaller collateral neurovascular bundle runs just superior to the lower rib of the space (in the order NAV from superior to inferior). Invasive procedures such as

thoracentesis Thoracentesis , also known as thoracocentesis (from Greek ''thōrax'' 'chest, thorax'— GEN ''thōrakos''—and ''kentēsis'' 'pricking, puncture'), pleural tap, needle thoracostomy, or needle decompression (often used term), is an invasive me ...

are performed with oblique entry of the instrument, directly above the upper margin of the relevant rib, to avoid damaging the neurovascular bundles.

Nerves

In reference to the muscles of the

thoracic wall The thoracic wall or chest wall is the boundary of the thoracic cavity. Structure The bony skeletal part of the thoracic wall is the rib cage, and the rest is made up of muscle, skin, and fasciae. The chest wall has 10 layers, namely (from ...

, the intercostal nerves and vessels run just behind the internal intercostal muscles: therefore, they are generally covered on the inside by the parietal

pleura The pulmonary pleurae (''sing.'' pleura) are the two opposing layers of serous membrane overlying the lungs and the inside of the surrounding chest walls. The inner pleura, called the visceral pleura, covers the surface of each lung and dips ...

, except when they are covered by the innermost intercostal muscles, innermost intercostal membrane,

subcostal muscles Subcostal may refer to: * Subcostal nerve * Subcostal arteries The subcostal arteries, so named because they lie below the last ribs, constitute the lowest pair of branches derived from the thoracic aorta, and are in series with the intercostal ar ...

or the

transversus thoracis muscle The transversus thoracis muscle (), also known as triangularis sterni, lies internal to the thoracic cage, anteriorly. It is usually a thin plane of muscular and tendinous fibers, however on athletic individuals it can be a thick 'slab of meat' ...

References

External links

* - "Structural organization within an intercostal space." * - "Thoracic Wall: The Anterior Thoracic Wall" Thorax (human anatomy) {{anatomy-stub