The anterior rami of the brachial plexus are the continuations of the anterior rami of spinal nerves C5-T1 . These rami emerge from the intervertebral foramina and travel through the neck. The five rami unite to form the superior, middle, and inferior trunks in the posterior triangle of the neck. Nerves C5, C6 unite to form the superior trunk; nerve C7 remains as the middle trunk; and nerves C8,T1 unite to form the inferior trunk. Portions of each trunk divide deep to the clavicle into an anterior and a posterior division. These primarily contain axons that innervate the anterior and posterior parts of the upper limb. Upon reaching the axilla, they converge to form three cords.
