Focal loss of anterior horn cells in the cervical cord in motor neuron disease.

In a three-dimensional study of the distribution of anterior horn cells in the C8 segment of the human spinal cord we have recognized lateral and medial zones of motor neuron groupings, but have not been able to recognize subgroups of neurons within these groupings resembling the anatomical columns described by earlier investigators. This observation does not invalidate the concept of functional groupings within these anterior horn cell pools. In studies of the same segment in cords obtained at autopsy from patients with motor neuron disease, zones of focal loss of motor neurons were identified, without consistent severity or distribution at different sectional levels. These findings imply varying resistance to the disease in different pools of motor neurons.