QUESTION: How do I assess impairment for a patient with a brachial plexus injury involving the middle and lower trunks but not the upper trunk?
ANSWER: Rating impairment for a brachial plexus injury using the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Sixth Edition, is straightforward. Table 15-20, Brachial Plexus Impairment: Upper Extremity Impairments (6th ed, 434-435), lists impairments for the entire brachial plexus, as well as upper, middle, and lower trunks individually, each in different rows. If both middle and lower trunks were injured, each would be rated, and the upper limb impairments combined per instructions number 8 and 13 on page 481.
The classic anatomic description of the brachial plexus describes the C5 through T1 nerve roots as contributing to the plexus, with the middle trunk composed of just the C7 nerve...
