Corpus: Intercostal space

The intercostal space, or ICS for short, is the space between two adjacent ribs.

Ribs and intercostal spaces

The intercostal space contains the following structures:

• Intercostal muscles
• Intercostal veins
• Intercostal arteries
• Intercostal nerves

In addition, the intercostal spaces contain lymphatic vessels that drain into the intercostal lymphatic nodes.

The intercostal spaces are critical landmarks for various diagnostic and therapeutic procedures. During cardiac auscultation, specific intercostal spaces are used to assess heart sounds:

• 2nd ICS, parasternal right: Aortic valve
• 2nd ICS, parasternal left: Pulmonary valve
• 4th ICS, parasternal right: Tricuspid valve
• 5th ICS, left midclavicular line: Mitral valve
• The Erb's point is located at the 3rd ICS, parasternal left

In the ECG lead according to Wilson, the electrodes are also partially attached according to the intercostal spaces.^[1]

During a minithoracotomy, the incision is often made in the 4th ICR.

The order of the intercostal pathways is easy to remember with 'VAN', vein at the top, nerve at the bottom, artery in between.