Spinal cord lesions

Examples: tumors, lymphoma, syringomyelia, vascular malformations

Spinal bone lesions

Examples: spondylosis, cervical rib, metastatic tumors

Infections

Examples: HIV, syphilis, myelitis, poliomyelitis, Lyme disease

Endocrine disorders

Examples: hyperthyroidism, hyperparathyroidism, diabetic radiculopathy

Toxins

Examples: lead, mercury

Other

Examples: postpolio syndrome, Huntington's disease, Friedreich's ataxia, sarcoidosis, multiple sclerosis, polymyositis, myasthenia gravis, muscular dystrophies