The anterolateral spinothalamic tract takes 2-3 segments to cross before entering the ascending anterolateral funiculus. Occur predominantly in middle decades. Descending autonomics may be affected causing bowel, bladder dysfunction. Spinal cord compression is dominated in the early stages by motor symptoms. Foramen magnum tumors present as a unique syndrome with a disproportionate loss of position and vibration sense in the upper as compared to the lower extremities, and with atrophy of the intrinsics of the hand.
Plain films show a variety of changes.
Myelography followed by CT is very useful. MRI is virtually mandatory to define the relationship of tumor to spinal cord and essential for intramedullary tumors. A large intraspinal and extraspinal mass is present causing displacement and distortion of the spinal cord. May be multiple in NF-1. Can assume a dumbell appearance.