Spinal Cord Injury (SCI) - Any injury to the spinal cord that is caused by trauma instead of disease.Depending on where the spinal cord and nerve roots are damaged, the symptoms can vary widely, frompain to paralysis to incontinence. Spinal cord injuries are described at various levels of "incomplete",which can vary from having no effect on the patient to a "complete" injury which means a total loss offunction.Your spinal cord is protected by the vertebral column (also known as the spinal column or backbone).The human spinal column is made up of 33 bones - 7 vertebrae in the cervical region, 12 in the thoracicregion, 5 in the lumbar region, 5 in the sacral region and 4 in the coccygeal region.The outer layer of the human spinal cord consists of white matter, i.e., myelin-sheathednerve fibers.These are bundled into specialized tracts that conduct impulses triggered by pressure, pain, heat, andother sensory stimuli or conduct motor impulses activating muscles and glands. The inner layer, or graymatter, is mainly composed of nerve cell bodies. Within the gray matter, running the length of the cordand extending into the brain, lies the central canal through which the cerebrospinal fluid circulates.A spinal cord injury (SCI) can occur anywhere along the spinal cord. It is the result of damage to cells inthe spinal cord and causes a loss of communication between the brain and the parts of the body below theinjury.Effects of a SCI may include low blood pressure, inability to regulate blood pressure effectively, reducedcontrol of body temperature, inability to sweat below the level ofinjury, and chronic pain.Complete and Incomplete Spinal cord Picture of the human spinal cordinjuries (SCI)Complete Spinal Cord Injury: Generally persons with a complete spinal cord injury suffer a loss ofsensation and motor ability caused by bruising, loss of blood to the spinal cord, or pressure on the spinalcord; cut and severed spinal cords are rare. Generally, complete spinal cord injuries result in total loss ofsensation and movement below the site of the injury.Incomplete Spinal Cord Injury: An incomplete spinal cord injury does not result in complete loss ofmovement and sensation below the injury site. These injuries are usually classified as:Anterior cord syndrome: Damage to the front of the spinal cord, affecting pain, temperature andtouch sensation, but leaving some pressure and joint sensation. Often motor function is unaffected.Central Cord Syndrome: Form of incomplete spinal cord injury in which some of the signals from thebrain to the body are not received, characterized by impairment in the arms and hands and, to a lesserextent, in the legs. Sensory loss below the site of the spinal injury and loss of bladder control may alsooccur. This syndrome, usually the result of trauma, is associated with damage to the large nerve fibers thatcarry information directly from the cerebral cortex to the spinal cord. These nerves are particularlyimportant for hand and arm function. Symptoms may include paralysis and/or loss of fine control ofmovements in the arms and hands, with relatively less impairment of leg movements. The brains abilityto send and receive signals to and from parts of the body below the site of trauma is affected but notentirely blocked.
Brown-Sequard syndrome: Injury to the lateral half of the spinal cord. The condition is characterizedby the following clinical features found below the level of the lesion - contralateral hemisensory anesthesiato pain and temperature, ipsilateral loss of propioception, and ipsilateral motor paralysis. Tactilesensation is generally spared.Spinal contusions: The most common type of spinal cord injury. The spinal cord is bruised but notsevered. Inflammation and bleeding occurs near the injury as a result of the injury.Injuries to individual nerve cells: Loss of sensory and motor functions in the area of the body towhich the injured nerve rootcorresponds.Cervical (neck)injuries (C1 - C8)C1 or atlasThe Atlas is the topmost vertebra,and along with C2, forms the jointconnecting the skull and spine. Itschief peculiarity is that it has nobody, and this is due to the fact thatthe body of the atlas has fused withthat of the next vertebra.C2 or axisForms the pivot upon which C1rotates. The most distinctivecharacteristic of this bone is thestrong odontoid process (dens) The spine is surrounded by many muscles and ligaments to give itwhich rises perpendicularly from strengththe upper surface of the body. Thebody is deeper in front than behind, and prolonged downward anteriorly so as to overlap the upper andfront part of the third vertebra.Injuries to C-1 and C-2 can result in a loss of many involuntary functions including the ability to breathe,necessitating breathing aids such as ventilators or diaphragmatic pacemakers.C4 (cervical vertebra)The fourth cervical (neck) vertebra from the top. Injuries above the C-4 level may require a ventilator forthe person to breathe properly.C55th cervical vertabrae down from the base of the skull, found in the neck. C5 injuries often maintainshoulder and biceps control, but have no control at the wrist or hand.C6 (cervical vertebra)
The sixth cervical (neck) vertebra from the top. The next-to-last of the seven cervical vertebrae. An injuryto the spinal cord between C6 and C7 vertebrae is called a C6-7 injury. These injuries generally allow wristcontrol, but no hand function.C7 or vertebra prominensThe most distinctive characteristic of this vertebra is the existence of a long and prominent spinousprocess, hence the name vertebra prominens. In some subjects, the seventh cervical vertebra is associatedwith an abnormal pair of ribs, known as cervical ribs. These ribs are usually small, but may occasionallycompress blood vessels (such as the subclavian artery) or nerves in the brachial plexus, causingunpleasant symptoms. C-7 and T-1 can straighten their arms but still may have dexterity problems withthe hand and fingers. Injuries at the thoracic level and below result in paraplegia, with the hands notaffected.C8Although there are seven cervical vertebrae (C1-C7), there are eight cervical nerves (C1-C8). All nervesexcept C8 emerge above their corresponding vertebrae, while the C8 nerve emerges below the C7 vertebra.In other words C8 is a nerve root not a vertebrae.Thoracic Vertebrae (T1- T12)The thoracic vertebrae increase in size from T1 through T12 andrepresent the 12 thoracic vertebrae. The thoracic vertebrae aresituated between the cervical (neck) vertebrae and the lumbarvertebrae. These thoracic vertebrae provide attachment for the ribsand make up part of the back of the thorax or chest.Damage or SCIs above the T1 vertebra affects the arms and thelegs. Injuries below the T1 vertebra affect the legs and trunk belowthe injury, but usually do not affect the arms and hands.Paralysis of the legs is called paraplegia. Human vertebra pictureParalysis of the arms AND legs is called quadriplegia.T-1 to T-8Most often control of the hands, but poor trunk control as the result of lack of abdominal muscle control.T-9 to T-12Allow good trunk control and abdominal muscle control. Lumbar and Sacral injuries yield decreasingcontrol of the hip flexors and legs. Individuals with SCI also experience other changes. For example, theymay experience dysfunction of the bowel and bladder.Lumbar Vertebrae (L1- L5)The lumbar vertebrae graduate in size from L1 through L5. These vertebrae bear much of the bodysweight and related biomechanical stress.
The lumbar vertebrae are the largest segments of the movable part of the vertebral column, and arecharacterized by the absence of the foramen transversarium within the transverse process, and by theabsence of facets on the sides of the body.Some individuals have four lumbar vertebrae, while others have six. Lumbar disorders that normallyaffect L5 will affect L4 or L6 in these individuals.L1The first lumbar vertebra is at the level as the ninth rib. This level is also called the important transpyloricplane, since the pylorus of the stomach is at this level.L3 - L5A lot of motion in the back is divided between these five motion segments with segments L3 - L4 and L4 -L5 taking most of the stress. L3 - L4 and L4 - L5 segments are most likely to breakdown from wear andtear causing such conditions as Osteoarthritis.L4 - L5 and L5 - S1The most likely to herniate (herniated disc, bulging disk, compressed disk, herniated intervertebral disk,herniated nucleus pulposus, prolapsed disk, ruptured disk, slipped disk). The effects of this can cause painand numbness that can radiate through the leg and extend down to the feet (sciatica).L5The fifth lumbar vertebra is the most common site of spondylolysis and spondylolisthesis.Sacral Spine (s1 - S5)The Sacrum is located behind the pelvis. Five bones (abbreviated S1 through S5) fused into a triangularshape, form the sacrum. The sacrum fits between the two hipbones connecting the spine to the pelvislocated just below the lumbar vertebrae.It consists of four or five sacral vertebrae in a child, which become fused into a single bone after age 26.The sacrum forms the back wall of the pelvic girdle and moves with it.The first three vertebrae in the sacral have transverse processes which come together to form wide lateralwings called alae. These alae articulate with the blades of the pelvis (ilium).As part of the pelvic girdle, the sacrum forms the back wall of the pelvis and also forms joints at the hipbone called the sacroiliac joints. The sacrum contains a series of four openings on each side through whichthe sacral nerves and blood vessels run. The sacral canal runs down the center of the sacrum andrepresents the end of the vertebral canal.Back pain or leg pain (sciatica) can typically arise due to injury where the lumbar spine and sacral regionconnect (at L5 - S1) because this section of the spine is subjected to a large amount of stress and twisting.People with rheumatoid arthritis or osteoporosis are inclined to develop stress fractures and fatiguefractures in the sacrum.