A representative C6 ventral horn on the lesioned side at 28 days after injury. Dashed lines indicate landmarks for motor neuron counting. A: Intradural avulsion group (group A). B: Intradural rhizotomy group (group B). C: Extra-vertebral avulsion group (group C). D: Extra-vertebral rupture group (group D). E: The unlesioned side (control). Compared with E, A and C showed an obvious decrease in the number of motor neurons. B showed a moderate decrease in the number of motor neurons. In D, almost all motor neurons survived (Bar: 200 μm.).