Severe traction on the upper limb in for example motor vehicle accident can lead to avulsion of the brachial plexus root sleeves or nerve roots. This is manifested clinically by upper limb weakness and sensory loss. 

CT myelography, conventional MRI and MR myelography are the methods of choice to detect nerve discontinuity as well as associated findings e.g. meningocele while MRI is more powerful to diagnose cord abnormalities e.g. edema, hemorrhage or myelomalacia and associated muscle atrophy or edema.