4th intercostal nerve

Nervus intercostalis IV

NervousNervesThoraxLeft and right

View left in 3D View right in 3D

What it is
The ventral ramus of the 4th thoracic nerve. It runs round the chest in the costal groove on the underside of the 4th rib, between the internal and innermost intercostal muscles and below the intercostal vein and artery, ending beside the sternum as an anterior cutaneous branch.
Function
Motor to the intercostal muscles; sensation from a band of skin (lateral and anterior cutaneous branches) and from the parietal pleura.
Size
About 2-3 mm thick; 27-32 cm long
Clinical note
Supplies the skin at the nipple (T4 dermatome) - the landmark used to map the level of a spinal-cord injury.

Nearby nervous structures 1st intercostal nerve, 2nd intercostal nerve, 3rd intercostal nerve, 5th intercostal nerve, 6th intercostal nerve, 7th intercostal nerve, T4 spinal nerve, T5 spinal nerve, T6 dorsal root ganglion, T6 spinal nerve