The brachial plexus refers to a complex web of large nerves that exit from the spinal cord in the neck and direct the movement and sensation of the entire upper limb. Traumatic brachial plexus injuries, which are most commonly sustained in high-speed motor vehicle accidents or while engaged in sporting events, affect the sensibility and muscle power in part of or the entire limb. Although some injuries to the brachial plexus improve on their own, others do not. Approximately 15% of brachial plexus injuries have an injury to the blood supply of the arm as well, and emergency surgery may be needed.
Figures A & B: CT myelogram showing a normal brachial plexus (left) and injured brachial plexus (right)
Brachial plexus injuries are unpredictable and usually require additional imaging or electrodiagnostic tests. Frequent and thorough examination over the first three to six months following injury is often necessary to document signs of nerve recovery.
An exam would include a physical examination of the upper extremity; starting with a neurologic examination, which is critical in evaluating upper extremity conditions, including neck, vascular, motor, sensory, and reflexes. The examiner would try to recreate symptoms sometimes associated with such an injury by having the patient bend his or her neck back and forth in various positions.
Electromyography (EMG) is a form of electrodiagnostic testing that is used to study nerve and muscle function and can provide specific information about the extent of nerve and/or muscle injury, the location of the injury, and give some indication whether the damage is reversible.
For more information about EMG testing, see A Patient’s Guide to EMG Testing