How does the distribution of weakness numbness or pain aid in differentiating neurogenic from muscular lesions?
Myopathies tend to cause proximal and symmetrical (bilateral) weakness and/or pain involving the shoulder girdle and hip girdle. If present, pain may be reported as aching or cramping.
Neuromuscular junction involvement presents with weakness involving ocular, bulbar, and proximal muscles without numbness or pain.
Peripheral neuropathies most commonly cause distal (hands and feet) numbness, weakness, and/or pain.
Nerve root compression causes asymmetric weakness and pain that may be either proximal or distal, depending on the level of the involved nerve root.
Spinal cord lesions usually are associated with a distinct sensory level around the trunk or abdomen if above the lumbar spine. Distal spastic weakness, often with impairment of bowel and bladder sphincter function, is also a feature of spinal cord disease.