Figure 3.

Ultrasound (US) and magnetic resonance image (MRI) of the right brachial plexus roots in a patient with upper extremity weakness after a motor vehicle accident. The US image at the interscalene triangle shows marked enlargement of the right C5 nerve root at the interscalene triangle, suspicious for a traction injury. The corresponding sagittal MRI of the right brachial plexus in the same patient shows abnormal enlargement and high signal of the C5 nerve root, confirming injury. ANT SCALENE, anterior scalene muscle.