1st intercostal nerve

Nervus intercostalis I

NervousNervesThoraxLeft and right

View left in 3D View right in 3D

What it is
The ventral ramus of the 1st thoracic nerve. It runs round the chest in the costal groove on the underside of the 1st 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; 17-22 cm long
Clinical note
The first intercostal nerve is tiny because most of T1 goes up into the brachial plexus; it has no anterior cutaneous branch.

Nearby nervous structures 2nd intercostal nerve, 3rd intercostal nerve, 4th intercostal nerve, 5th intercostal nerve, 6th intercostal nerve, T1 spinal nerve, T2 spinal nerve, T3 spinal nerve, T4 spinal nerve, T5 spinal nerve