The brachial plexus is formed by which ventral rami?

The brachial plexus is formed by which ventral rami?

• A. anterior rami of C5-T1
• B. posterior rami of C5-T1
• C. anterior rami of L2-L5
• D. dorsal rami of C3-C8

Answer: (A)

The brachial plexus is formed by the ventral (anterior) rami of spinal nerves from C5 through T1. These ventral rami come together in the lower neck to give rise to trunks, divisions, cords, and branches that innervate the upper limb. The posterior rami do not contribute to this plexus; they primarily supply the back. The lumbar plexus, not the brachial plexus, is formed from L2-L5, and the dorsal rami of C3-C8 supply the back rather than the upper limb. So the anterior rami of C5-T1 best explain the formation of the brachial plexus.

The brachial plexus is formed by the ventral (anterior) rami of spinal nerves from C5 through T1. These ventral rami come together in the lower neck to give rise to trunks, divisions, cords, and branches that innervate the upper limb. The posterior rami do not contribute to this plexus; they primarily supply the back. The lumbar plexus, not the brachial plexus, is formed from L2-L5, and the dorsal rami of C3-C8 supply the back rather than the upper limb. So the anterior rami of C5-T1 best explain the formation of the brachial plexus.