Intercostal space

[2][3] These muscles help to move the ribs during breathing.

[3] The neurovascular bundle has a strict order of vein-artery-nerve (VAN), from top to bottom.

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

[2] In reference to the muscles of the thoracic wall, the intercostal nerves and vessels run posterior to the internal intercostal muscles: therefore, they are generally covered on the inside by the parietal pleura, except when they are covered by the innermost intercostal muscles, innermost intercostal membrane, subcostal muscles or the transversus thoracis muscle.