Which of the following components of his white matter has most likely been damaged?

Following a spinal cord injury suffered in a motor vehicle accident, a 22-year-old male has lost fine motor function of his finger and thumb, but is still able to perform gross motor movements of his hand and arm. Which of the following components of his white matter has most likely been damaged? (Points : 0.4)
The inner layer (archilayer)
The middle layer (paleolayer)
The outer layer (neolayer)
The reticular formation