T1 spinal nerve

Nervus spinalis T1

NervousNervesThoraxLeft and right

View left in 3D View right in 3D

What it is
The T1 spinal nerve leaves the spinal canal between T1 and T2. Its sensory (dorsal) and motor (ventral) roots meet just beyond the dorsal root ganglion; the short mixed nerve then splits into a small dorsal ramus for the back muscles and skin and a larger ventral ramus, which joins the brachial plexus (a small part forms the first intercostal nerve).
Function
Carries motor fibres to the muscles of its segment (myotome) and sensation back from its strip of skin (dermatome): the medial side of the arm and forearm.
Size
About 4-5 mm thick; the mixed nerve is only ~1 cm long before it divides
Clinical note
Supplies the small muscles of the hand. An apical lung (Pancoast) tumour invading T1 and the sympathetic chain gives hand wasting with a Horner syndrome.

Nearby nervous structures 1st intercostal nerve, 2nd intercostal nerve, 3rd intercostal nerve, 4th intercostal nerve, T2 spinal nerve, T3 spinal nerve, T4 spinal nerve, T5 spinal nerve, T6 dorsal root ganglion, T6 spinal nerve