The thoracic spine comprises 12 vertebrae that descend from the shoulders though the rib cage. The spine contains a channel down its center, in which the spinal cord is located. Openings between the thoracic vertebrae, called foramina, allow the spinal nerves to leave the central nervous system and pass into the peripheral nervous system, where they supply nerve impulses that support motor, sensory and visceral functions. Stenosis refers to a narrowing of the channels through which the nerves and spinal cord pass. Spinal stenosis can compress nerves and adversely influence sensory, motor or organ function, causing a variety of symptoms.
Respiratory Disturbances
MedlinePlus, a service of the National Library of Medicine and the National Institutes of Health,
notes that even minor injuries can cause spinal cord trauma in patients whose spinal canal has become stenotic. Injuries at the thoracic level in such patients can lead to paralysis of the muscles of respiration and cause symptoms such as difficulty breathing.
Pain, Numbness or Paresthesia
When the spine or spinal nerve roots are compressed by stenosis in the vertebral canal or in the foramen, nerve inflammation can ensue, leading to pain. The location of these symptoms will most likely be in the area below the level of nerve injury, and thoracic stenosis can cause symptoms that extend into the legs, according to MedlinePlus. At times the nerve impulses will be disrupted to the point where the patient experiences complete numbness in the affected areas. Paresthesia, a tingly "pins and needles" sensation, is another sensory disturbance associated with stenosis.
Muscle Weakness, Spasticity or Paralysis
Spinal stenosis can affect the motor neurons and disrupt the muscles that they serve. In addition to respiratory difficulties prompted by compression of the motor neurons to the muscles used in breathing, motor nerve disturbances caused by thoracic stenosis can adversely affect the leg muscles. These can manifest in symptoms such as spasticity, or uncontrollable movements, due to overactive muscle tone, or it can have the opposite affect and result in muscle weakness, or in extreme cases, paralysis. Muscle weakness due to thoracic stenosis can result in gait disturbances. Dr. Mark Palumbro of the Department of Orthopaedic Surgery at Case Western Reserve University School of Medicine has found that surgical treatment of thoracic spinal stenosis can be effective in alleviating gait disturbances, but that recurrent stenosis can cause the symptoms to return over the long-term.
Vascular Disturbances
The upper thoracic levels of the spine contain nerves that affect the muscle tone of blood vessel walls. Stenosis in the upper thoracic levels can result in blood pressure disturbances, according to MedlinePlus. Lowered blood pressure due to nerve damage can lead to orthostatic hypotension, a condition that causes dizziness upon sudden positional changes.
