What nerve root levels does the brachial plexus emerge from?

What nerve root levels does the brachial plexus emerge from?

• A. C4, C5, C6, C7
• B. C5, C6, C7, C8
• C. C5, C6, C7, C8, T1
• D. C5, C6, C7, C8

Answer: (C)

The brachial plexus develops from five ventral root nerves that emerge in the neck and upper chest: C5, C6, C7, C8, and T1. These five roots form the foundation for the entire plexus and give rise to all the nerves that supply the upper limb. That’s why the standard range includes T1; it completes the lower end of the plexus. C4 isn’t part of the primary roots that form the brachial plexus (though it can contribute to other nearby nerves in some variations), so it isn’t included. Being aware that the lower root is T1 helps explain why this full five-root set is correct.

The brachial plexus develops from five ventral root nerves that emerge in the neck and upper chest: C5, C6, C7, C8, and T1. These five roots form the foundation for the entire plexus and give rise to all the nerves that supply the upper limb. That’s why the standard range includes T1; it completes the lower end of the plexus. C4 isn’t part of the primary roots that form the brachial plexus (though it can contribute to other nearby nerves in some variations), so it isn’t included. Being aware that the lower root is T1 helps explain why this full five-root set is correct.