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Spinal Nerves

The nervous system is divided into two systems:

The Central Nervous System (CNS) consists of the brain and the spinal cord. The spinal cord is the continuation of the brain which lies protected within the bones of the spine. You can think of the CNS as the control center for the body. It allows us to think, create memories, speak, move, run, etc. 

The Peripheral Nervous System (PNS) consists of 12 cranial nerves, and 31 pairs of spinal nerves.  The PNS acts as the system of electrical wires that allows for communication between the CNS and the body’s muscles and sensory receptors. They also control the automatic functions of the bowel, bladder, respiratory (breathing), and heart function. Essentially, the PNS sends signals from the brain to the muscles of our body so that they can contract, which leads to movement. The PNS also relays information regarding sensation from the sensory receptors of our body to our brain, so we can feel the environment around us. 

The spinal nerves are named according to where in the spine they emerge i.e. they are named in accordance with the level of the spine they exit from. E.g. the C2 nerve exits between the C1-2 vertebrae, the L4 nerve exits between the L4-5 vertebrae.  As you can see in the Lumbar segment, spine, nervesimage to the left, the nerve roots (in red) branch off from the spinal cord to create the electrical wires of the PNS

It will be helpful to review the anatomy of the cervical and lumbar spines before continuing on below. 

 

 

Spinal Nerves 

There are 31 pairs of spinal nerves. Again, they are named according to where they each exit in the spine (see figure below).  

Relation of Spinal Nerves to Vertebrae

Each spinal nerve is attached to the spinal cord by two roots: a dorsal (or posterior) root which relays sensory information and a ventral (or anterior) root which relays motor information. Therefore, once the two roots come together to form the spinal nerve, the nerve carries a combination of both sensory and motor information (i.e. it contains mixed fibers). 

The fibers of the sensory root carry sensory impulses from the body to the spinal cord, which ultimately relays that information to the brain. Sensory impulses include — pain, temperature, vibration, touch, and position sense (proprioception)—from organs, tendons, joints, and body surfaces.

There is a specific pattern to how nerves carry sensory information from our skin to our brain.  Each spinal nerve carries sensory information from specific regions of our skin. These regions are called dermatomes (see below)

Dermatomes of the right shoulder, arm and hand.

 

 

The motor roots carry impulses from the brain and spinal cord to the muscles of the body.  These allow us to control the many muscles in our bodies. 

The spinal nerves are divided into four main categories of spinal nerves based on the location from which they branch  

  • 8 cervical (C1-C8) nerves emerge from the cervical spine (neck) 
  • 12 thoracic (T1-T12) nerves emerge from the thoracic spine (mid back)
  • 5 lumbar (L1-L5) nerves emerge from the lumbar spine (lower back)
  • 5 sacral (S1-S5) nerves emerge from the sacrum (the triangular bone at the base of the spine)
  • 1 coccygeal nerve emerges from the coccyx (the tailbone)

 

Nerve Plexuses

It is important to mention that after the spinal nerves exit from the spine, they join together to form four paired clusters of nerves, or nerve networks, called plexuses.

  • Cervical Plexus – the cervical plexus represents the continuation of the upper cervical spinal nerves that gives innervation (i.e. supplies nerve function) to the neck and shoulders
  • Brachial Plexus – the brachial plexus represents the continuation of the lower cervical spinal nerves that gives innervation to the upper back, shoulder, arms, and hand. 
  • Lumbar Plexus – the lumbar plexus represents the continuation of lumbar spinal nerves that gives innervation to the lower extremities
  • Sacral Plexus – the sacral plexus gives innervation to the back of the thigh, leg, bottom of the foot, as well as the pelvis

More information about your nerves, spine and back:

Comments

  1. Cheryl Avery says

    10/1/16 I experienced a sudden pain in the small of my back & behind both thighs. Within 2-3 minutes I collapsed & was unable to move my lower extremities. After PT I am able to walk in a pool! I still have no sensation to heat or cold, I have touch but minimal pain, other than resent (?) nerve pain in my lower legs. What nerve was damaged? The MRI suggested plaque traveled from my aorta and lodged on a nerve, damaging the anterior portion of my spinalcord. Unfortunately I don’t recall the doctor that cared for me at Northwestern in Chicago. I am 71. 2/20/48

  2. Robert Cherry says

    I have had nerve damage in my lower limbs for over 4 years now I have degenerative vertebrae in my neck c4-7 I had a bycicle accident and landed on my neck which caused the nerve damage in my limb’s I also have a tingling sensation in my lower arms and fingers I had spinal cord damage as well but that was only slightly damaged but my problem is when I walk my legs get very weak and I feel the nerves in my legs getting worse as time goes by what is a person supposed to do if your go doesn’t seem to know what to do

  3. I have 2 nerves that are “crushed” according to my dr. One full report actually says obliterated. A ton of shoulder and arm pain in one the other is just numb and almost done like dead weight. I have to wait until Sept for surgery due to specific reasons. What can I do in the mean time? Also, chin to chest, the cervical spine physically hurts.

  4. Nur Mohammad says

    My uncle got an accident a few days before(20-22days). He injured in his cervical spine vertebrae most probably C1 or C2. He is suffering from respiratory distress. The doctor said he could not able to move his body parts again, in summary, they called it paralyzed. Moreover, they said his body condition will be decreased day by day. His body parts are damaging and eventually, all the body parts will be damaged soon. Currently is at ICU taking full life support. he could survive without life support. The doctor also said within a few days he will be no more. Is there any treatment for this problem. We are feeling helpless as he is only 36 years old.

  5. Patricia Martin, the symptoms you’re experiencing are consistent with perineural or Tarlov Cyst Disease. These “cysts” are not your typical cysts that can just be removed. They’re a herniation of the dura (outer layer of spinal cord)) and are filled with spinal fluid. The cysts develop on nerve roots, and therefore are part of the nerve and cannot be removed. They have to be surgically drained and wrapped by one of the three tc specialists in the country. You can find more information about them on the Tarlov Cyst Disease Foundation website. The only thing you’re experiencing that is not consistent with tc’s are the knots everywhere. Tc’s can’t be felt because they are deep within the spine. However because the nerves affect a lot of different things, they can cause muscle spasms, knots, etc. I suggest that you get an mri of your sacrum/pelvis with and without contrast to check for Tarlov cysts.

  6. I have pain in my shoulder blade and arm when I turn my head to the right, it says to sit on your right hand and turn head to the left and right and it will relieve the pain, which it dose but if im not doing that its still happens what can I do to make it go away permanently.

  7. Patricia Burnice Martin says

    Half way down my spine I have these small knots either next to my spine or several inches from my spine I believe is comming from the nerves in my spine. I get severe pain in my legs to the point I have dreams of not being able to walk. I thought there was 9 of those knots but as far down as my tail bone I have those and if I stretch my legs I can feel equally bad pain on the back inner side of my thighs, so i began pushing around the area tring to locate the pain and I found many more of those knots from below my behind all the way down to my knee, omg so painful. They are definitely all over my nerves comming down my legs. My legs swell and my hand and feet, legs and arms off fall asleep with tingling . I get sharp pains shooting down my legs and often my legs feel like they are on fire. It’s a struggle to walk but I have no choice to work , anyone with any ideas what those knots are or what may be my issue? Appreciate any help.

  8. Can a large disc bulge (C5-C6) and a moderate one (C6-C7) and pinching nerve cause your appetite to change? I had a bad viral infection back in August and was out sick for a week and a half. After that I didn’t want to eat the same foods anymore. So many things that I used to like to eat sound gross now, to include beer, which I loved the taste of before. I’m not sure how my disc became this way, I’ve had neck pain since Jun of 18, but when I was sick, I threw up so hard I’m not sure if that didn’t cause the disc to bulge. Either way, I’m not sure what caused my appetite to change. Any thoughts?

  9. Justin oliphant says

    Middle aged male I have been through the ringer.4 years ago was diagnosed with palsy in left hand.Had a tendon swap surgery. After a year the left hand wouldn’t open. The so s months of P.T. nothing was going my way. Then was receiving steroid injections,,pinpiont, in shoulders Roto cuff. Nothing. The pain was.moderate and I was taking three oc5’s daily and gabapintin 3x daily and had mild relief.. After the 4th year I had a neck M.R.I and head. Bingo,,c4 compressed root,c6 comprresed root c7 t1 thecal sac compression,,c4and 5 severe right sided stenosis with uncomfortable spurring. Legs and arms and back of thumbs and forearms numb and annoyingly paiinful..taking xararto for a,fib,been in cardiac arrest and had a quad bypass. Fron the bypass I have a midline henia,subxizion that is approx. 5 centimeters. Both Roto cuffs are torn also..I was told I may need 6 surgeries but the heart doctor won’t give the green light.. So narcotics and nerve Rx’s and blood thinners are what I take.I am an electician so exercise just on the job requirements helps too. No pain no gain or brains ..Good luck to you all out there suffering..lol
    N

  10. Cindy Schmidler says

    Chest pain can be a serious symptom of a variety of illnesses, please see your primary care physician for a more accurate diagnosis.

  11. I have scoliosis at T 6 – T 7
    now i have developed Chest pain that is present every time and increased by movement and coughing
    Is this because of scoliosis

  12. I would just like the names of the cervical nerves, but I can’t find the answer ?¿?

  13. Jennifer davis says

    Nerve blocks last for how long

  14. Shivam Vishwakarma BPT says

    If you. Have any nearest physiotherapist .you go on there and take treatment according to the therepist

  15. Rana Muhammad Ali says

    i m patient of T1W1, T2W2, L4 and L5-S1. accordingly to the MRI Lumbosacral Spinal shows these diagonisis. Doctor has advised me to strict bed rest for almost three months with medicines i.e. Methycobol Inj 1ampule after one day, caflm 50 tab 1+1, and Gablin 75mg 1+1. Kindly suggest any health implication if i could not recover from the said disease within stipulated time as stated above.

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