A neuromuscular disorder that results in the loss of motor neurons and progressive muscle wasting.

(anatomy) A single unpaired artery that is formed by the anastomosis of a branch of the vertebral artery on each side and that descends in the anterior median fissure of the spinal cord.

(anatomy) Either of two arteries of which one arises from a vertebral artery on each side below the level at which the corresponding branch of the anterior spinal artery arises and which descend on the posterior lateral surface of the spinal cord along a line passing close to the entrance of the dorsal roots to the spinal cord.

plural of posterior spinal artery

plural of spinal butterfly ray