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Thread: which part of the spinal cord runs what?

  1. #1
    Member beelady's Avatar
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    May 2003
    Winthrop, MN USA

    which part of the spinal cord runs what?

    When my son was injured Dec. 14, 2002 our heads were in the clouds when everything was explained to us. I have requested info from the hospital about his injury which I havent received yet but I have one question about the spinal cord. Is there a particular "part" of the cord that runs motor skills and the other that runs sensory? My husband thinks we were told the back runs sensory and the front runs the motor skills. Our son broke his C7 and they had to remove the front and put a bone and plate in there and then in the back they removed a bone fragment. He has always since day 1 had feeling coming back and has his abs and back muscles but as of yet the only thing he can do with his legs is turn off those jerky spasms.

  2. #2
    beelady, your husband has described it correctly. Most of the axons that carry motor information are indeed situated in the ventral or front part of the spinal cord while most of the axons that carry sensory information are located in the "back" or dorsal part of the spinal cord.

    I am glad that he is getting function back. I am impressed if he can voluntarily turn off the spasms in the legs. This means that he has significant descending inhibitory influences on the lower spinal cord.

    He is still early after spinal cord injury. Most people do not recover 90% of their function until 12-24 months after injury. He still has substantial recovery in front of him.


  3. #3
    Of course the degree of deficit is different for each person, depending on the exact level of injury, mechanism of injury (crush, cut, bruise, ischemia, swelling, etc.), and completeness of injury.

    What is his neurologic level of injury and his ASIA classification?

    Very simplistically, you can think of the white matter (outter rim of the spinal cord like a large cable with wires (nerve fibers) running down the cable from the brain (motor nerves) and from the peripheral nerves of the body up the cable to the brain (sensory nerves). Each of the functioned and areas supplied to or from the spinal cord is grouped together in bundles of similar nerves called tracts. There are tracts for sensory functions and tracts for motor functions. Each of the tracts is further subdivided into the areas of the body supplied.

    The gray matter (inner core) of the cord is made up of lower motor neuron cell bodies, which get messages from the brain through the white matter axons, then send messages out from the cord through their neurons. The gray matter is similary organized into groups of cells called lamina.

    Here is a diagram showing some of the more important tracts in colors:

    As a rule, in the cervical area, nerves running through the middle part of the cord are more likely to innervate the arms, while those on the peripherary are more likely to innervate the legs and trunk.

    1. Fasciculus gracilis (part of the posterior white columns: position sense, vibration, pressure)
    2. Fasciculus cuneatus (part of the posterior white columns: position sense, vibration, pressure)
    3. Dorsal Spinocerebellar tract (sensory information to the cerebellum in the brain: muscle tension, posture, balance info mostly)
    4. Lateral corticospinal tract (the major voluntary motor tract, information from the motor centers in the brain, mostly trunk and legs)
    5. Lateral Spinothalamic tract (the major sensory tract for pain and temperature information)
    6. Ventral spinocerebellar tract (sensory information to the cerebellum in the brain: muscle tension, posture, balance info mostly)
    7. Rubrospinal tract (moderating motor information from the red nucleus area of the brain, can inhibit or facilitate movement, facilitates activity of flexor muscles and inhibits extensors)
    8. Spinotectal tract (additional small pain tract)
    9. Anterior Corticospinal tract (additional small motor tract from the brain, primarily arm movement)

    These tracts are less understood. Perhaps Dr. Young can provide some good basic information on them.

    10. Olivospinal tract
    11. Spinoolivar tract
    12. Tectospinal tract (Reflex postural movement in response to visual and auditory stimuli)
    13. Reticulospinal tract (information from the reticular formation and cerebellum in the brain)
    14. Vestibulospinal tract (information from the vestibular areas and cerebellum of the brain having to do with balance)
    15. Anterior spinothalamic tract (sensory information to the brain)


  4. #4
    Member beelady's Avatar
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    May 2003
    Winthrop, MN USA
    He is a C8 and is classified Asia B.

    [This message was edited by SCI-Nurse on 07-16-03 at 08:35 PM.]

  5. #5
    I am impressed if he can voluntarily turn off the spasms in the legs. This means that he has significant descending inhibitory influences on the lower spinal cord.
    Plaese explain what "descending inhibitory influences on the lower spinal cord" mean. is it a positive sign? my daughter has been able to turn off her jerking spasms in her legs eversince she got the spasms for the first time after the C7 decompressive surgery.
    Thank you in advance.

  6. #6
    More than half of the motor messages coming from the brain down the spinal cord are inhibitory. These are messages that tell your body NOT to do something (largely reflex activity). Very simplistically, this is why AB people do not have spasticity or spasms, and why they are not incontinent of urine or stool.

    If someone can voluntarily inhibit spasms (or other reflex activity) it means they have a significant number of nerve fibers intact leading from the brain through their injury level and on down the spinal cord to the important lower motor neurons. This means the injury is fairly incomplete.


  7. #7
    Member beelady's Avatar
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    May 2003
    Winthrop, MN USA
    96 long ago was your daughters surgery. My son also broke the C7 and had surgery to remove and replace with a bone and plate. Jess was injured Dec. 14, 2002 and is now in therapy at Project Walk in California.

  8. #8
    My daughter had an epidural bleeding of unknown etiology that put compression on her spinal cord at C-7 and T-1 on July 13, 2002.
    The local doctors ordered decompressive laminectomy on July 15, 2002, which was too late for her full recovery(negligence and departure form acceptable standard of care).
    She was evaluated as ASIA B after the surgery. The ASIA score improved to ASIA C (June 6, neurological examination. Most of her recovery came after we left hospital in October 31,2002. She has been doing phisical therapy three times a week 45 min each, at the local rehab center, on and off aquatic therapies and home exercises.
    Her muscles in the thoracic area become pretty strong (she sits without support and is able to get up to a sitting position without much effort)her hips are even much stronger and her quadriceps work fine, now.
    All these muscles returned very gradually over several months. She can take steps using long leg braces and support of a walker. Her therapist wants to use crutches in the
    near future.She sterted ambulatory training in end of January 2003. Also she walks in the swimming pool with a walker and knee immobilizers that lock her knees.Since the surgery she has had pretty good sensation under injury level, slightly diminishing towards her
    toes. She can feel when she needs to go to the bathroom. That came around April .

    We still hope for more recovery for my daughter

  9. #9
    hallina and beelady,

    I am hearing good news from both of you. ASIA B means that Beelady's son has some sensory information coming all the way from the bottom of the spinal cord. The fact that both have have sensation down into the legs and even some motor control, inhibitory as well as excitatory, suggest that there is further recovery ahead. If a person can sense bladder fullness, that is usually the first step towards recovery and control of bladder function. Finally, as Hallina already knows, recovery takes place slowly and continues for more than a year.

    I like KLD's explanation. Let me just add a bit more to it. The spinal cord contains much of the circuitry necessary for function. What the brain does is initiate movement and then modulate the activity with inhibitory and excitatory signals. As little as 10% of the white matter (fiber tracts) in the spinal cord can support remarkably good walking.

    The recent discovery that intensive and repetitive ambulation training can restore locomotor function has introduced a new concept to rehabilitation. In addition to building muscle, the training is inducing plasticity in the spinal cord, to recruit circuits that have been turned off due to the injury or to inactivity after the injury.

    Milan Dimitrijevic (a very experienced neurologist who had deep insights into spinal cord injury) said in the 1980's, that the injured spinal cord is building a new nervous system. It has its own rules and can do things that defies conventional wisdom. He coined the phrase "discomplete" for people who are recovering from severe injuries, emphasizing that the spinal cord is utilizing structures and connections that it normally does not use in order to function.

    There are so many tools today that we did not have even a decade ago, to promote functional recovery.


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