A careful history and detailed examination, with a sound appreciation of the anatomy, will reveal the nature of the lesion in only 60% of cases. Associated vascular (15%) and musculoskeletal injuries are common.
Root avulsions occur proximal to the dorsal root ganglion, with loss of dorsal sensibility and denervation of dorsal neck muscles; plexus ruptures occur more distally. Mapping sensory and motor defects gives a good indication of the nature of the injury. Paralysis of the rhomboids or serratus anterior implies a proximal, usually preganglionic lesion, at the C5 or C6 level, respectively. Horner's sign (ptosis, miosis, anhidrosis, enophthalmos) implies a preganglionic C8/T1 lesion of the cervical sympathetic chain.
Chest, cervical spine and shoulder X-rays are mandatory. Further assessment with EMG studies may be necessary to localize the site of the injury. Supraclavicular injuries may need investigation with a CT myelogram or MRI, if surgery is contemplated. In cases of root avulsion pseudomeningoceles may be seen, which alter the prognosis and management. Investigation should be delayed a few weeks to allow CSF leaks to seal.
At a later stage, usually 3-4 weeks, the development of Tinel's sign implies recovery of a postganglionic injury - a favourable prognostic sign.
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