Brachial plexus

The brachial plexus is a group of nerves. It runs from the vertebral column to the arm. 

Structure
The brachial plexus is divided into five roots, three trunks, six divisions, three cords, and five branches. 

Roots
The five roots come out of the spinal cord. They are each named after the part of the spinal cord they come out of: C5, C6, C7, C8, and T1.

Trunks
These roots join to form three trunks:
 "upper" (C5-C6)
 "middle" (C7)
 "lower" (C8-T1)

Divisions
Each trunk then splits into two divisions:
 anterior (front) divisions of the upper, middle, and lower trunks
 posterior (back) divisions of the upper, middle, and lower trunks

Cords
These six divisions join up again to become the three cords. 
 The posterior cord is formed from the three posterior divisions of the trunks (C5-C8,T1)
 The lateral cord is formed from the anterior divisions of the upper and middle trunks (C5-C7)
 The medial cord is simply a continuation of the anterior division of the lower trunk (C8,T1)
Diagram

Nerves
The nerves that come out of the brachial plexus include:
 Radial nerve
 Axillary nerve
 Musculocutaneous nerve
 Median nerve
 Ulnar nerve

 Related pages 
Brachial artery

Category:Nervous system