The motor examination is a critical component of the patient’s examination when it comes to surgical planning. It is helpful to make a list of what muscles are functioning and not functioning (i.e., what’s in/what’s out) in order to decide what treatment options are available to improve function.
In straightforward injuries, it may be possible to hone in on the examination of a specific nerve because it is clear that, for example, the ulnar nerve is transected at the mid forearm. The motor exam for this injury is therefore organized by nerve:
• Examine the ulnar nerve-innervated muscles to confirm level of loss of function.
• Examine the median nerve-innervated muscles to confirm possible donor nerve function for nerve transfer procedures.
For a more complex injury such as a multi-root level brachial plexus injury, doing a complete motor exam organized by region or joint is recommended.
• Although the exam could be organized by nerve, this would confuse the issue since discrete nerves are not injured -- instead the cervical roots that provide contributions to those nerves are the ones injured.
• Therefore systematic examination starting proximally and moving distally ensures that nothing is missed.