A<unk>  is a lesion which affects nerve fibers traveling from the anterior horn of the spinal cord to the relevant muscle(s) -- the<unk><unk>  neuron.
Lower motor neuron lesion
Upper motor neuron lesion
Motor neuron disease
Hereditary motor and sensory neuropathy
Adrenomyeloneuropathy
Acute motor axonal neuropathy
Spinal autonomic dysreflexia
Spinal cord tumor