Spinal cord injuries cause
myelopathyMyelopathy refers to pathology of the spinal cord. When due to trauma, it is known as spinal cord injury. When inflammatory, it is known as myelitis. Disease that is vascular in nature is known as vascular myelopathy....
or damage to
white matterWhite matter is one of the two components of the central nervous system and consists mostly of myelinated axons. White matter tissue of the freshly cut brain appears pinkish white to the naked eye because myelin is composed largely of lipid tissue veined with capillaries. Its white color is due to...
or myelinated fiber tracts that carry signals to and from the brain. This type of traumatic injury could also damage the gray matter in the central part of the cord, causing segmental losses of interneurons and motorneurons. Spinal cord injury can occur from many causes, including:
- Trauma such as automobile crashes, falls, gunshot
A firearm is a device which projects either single or multiple projectiles at high velocity through a controlled explosion. The firing is achieved by the gases produced through rapid, confined burning of a propellant. This process of rapid burning is technically known as deflagration...
s, diving accidentsDiving is the sport of jumping or falling into water from a platform or springboard, sometimes while performing acrobatics. Diving is an internationally-recognized sport that is part of the Olympic Games. In addition, unstructured and non-competitive diving is a recreational pastime.Diving is one...
, war injuriesA casualty is a person who is the victim of an accident, injury, or trauma. The word casualties is most often used by the news media to describe deaths and injuries resulting from wars or disasters...
, etc.
- Tumor such as meningioma
Meningiomas are the second most common primary tumor of the central nervous system, arising from the arachnoid "cap" cells of the arachnoid villi in the meninges. These tumors are usually benign in nature; however, they can be malignant.-Causes:...
s, ependymomaEpendymoma is a tumor that arises from the ependyma, a tissue of the central nervous system. Usually, in children the location is intracranial, while in adults it is spinal. The common location of intracranial ependymoma is the fourth ventricle...
s, astrocytomaAstrocytomas are cancers of the brain that originate in star-shaped brain cells called astrocytes.They account for roughly 75% of neuroepithelial tumors.-Grading:...
s, and metastaticMetastasis , or metastatic disease, sometimes abbreviated mets, is the spread of a disease from one organ or part to another non-adjacent organ or part...
cancer.
- Ischemia resulting from occlusion of spinal blood vessels, including dissecting aortic aneurysms
An aortic aneurysm is a general term for any swelling of the aorta, usually representing an underlying weakness in the wall of the aorta at that location...
, emboli, arteriosclerosisArteriosclerosis refers to a stiffening of arteries.Arteriosclerosis is a general term describing any hardening of medium or large arteries...
.
- Developmental disorders, such as spina bifida
Spina bifida is a developmental birth defect caused by the incomplete closure of the embryonic neural tube. Some vertebrae overlying the spinal cord are not fully formed and remain unfused and open. If the opening is large enough, this allows a portion of the spinal cord to stick out through the...
, meningomyolcoele, and other.
- Neurodegenerative diseases, such as Friedreich's ataxia
Friedreich's ataxia is an inherited disease that causes progressive damage to the nervous system resulting in symptoms ranging from gait disturbance and speech problems to heart disease...
, spinocerebellar ataxiaSpinocerebellar ataxia is a progressive, degenerative, genetic disease with multiple types, each of which could be considered a disease in its own right.-Symptoms:...
, etc.
- Demyelinative diseases, such as Multiple Sclerosis
Multiple sclerosis is an idiopathic disease of suspected autoimmune cause, in which the body's immune response attacks a person's central nervous system , leading to demyelination. Disease onset usually occurs in young adults, and it is more common in females...
.
- Transverse myelitis, resulting from stroke, inflammation
Inflammation is the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli as well as initiate the healing process for the tissue. Inflammation is not a...
, or other causes.
- Vascular malformations, such as arteriovenous malformation
Arteriovenous malformation or AVM is an abnormal connection between veins and arteries, usually congenital. This pathology is widely known because of its occurrence in the central nervous system, but can appear in any location....
(AVM), dural arteriovenous fistulaA dural arteriovenous fistula , also called a dural arteriovenous malformation , is an abnormal direct connection between a meningeal artery and a meningeal vein or dural venous sinus.-Classification:...
(AVF), spinal hemangiomaA hemangioma of infancy is a benign self-involuting tumour of endothelial cells . In most cases it appears during the first days or weeks of life and will have resolved at the latest by age 10...
, cavernous angiomaCavernous angioma, also known as cerebral cavernous malformation , cavernous haemangioma, and cavernoma, is a vascular disorder of the central nervous system that may appear either sporadically or exhibit autosomal dominant inheritance....
and aneurysmAn aneurysm or aneurism , is a localized, blood-filled dilation of a blood vessel caused by disease or weakening of the vessel wall....
.
Classification
The American Spinal Injury Association (ASIA) defined an international classification based on neurological responses, touch and pinprick sensations tested in each dermatome, and strength of ten key muscles on each side of the body, i.e. shoulder shrug (
C4The cervical spinal nerve 4 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 4 .It's control of the thoracic diaphragm has inspired a medical mnemonic: "Cut C4, breathe no more."...
), elbow flexion (
C5The cervical spinal nerve 5 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 5 ....
), wrist extension (
C6The cervical spinal nerve 6 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 6 ....
), elbow extension (
C7The cervical spinal nerve 7 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 7 ....
), hip flexion (
L2The lumbar spinal nerve 2 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 2 .-Muscles:...
).
Traumatic spinal cord injury is classified into five categories by the American Spinal Injury Association and the International Spinal Cord Injury Classification System:
- A indicates a "complete" spinal cord injury where no motor or sensory function is preserved in the sacral segments S4-S5.
- B indicates an "incomplete" spinal cord injury where sensory but not motor function is preserved below the neurological level and includes the sacral segments S4-S5. This is typically a transient phase and if the person recovers any motor function below the neurological level, that person essentially becomes a motor incomplete, i.e. ASIA C or D.
- C indicates an "incomplete" spinal cord injury where motor function is preserved below the neurological level and more than half of key muscles below the neurological level have a muscle grade of less than 3, which indicates active movement with full range of motion against gravity.
- D indicates an "incomplete" spinal cord injury where motor function is preserved below the neurological level and at least half of the key muscles below the neurological level have a muscle grade of 3 or more.
- E indicates "normal" where motor and sensory scores are normal. Note that it is possible to have spinal cord injury and neurological deficits with completely normal motor and sensory scores.
In addition, there are several clinical syndromes associated with incomplete spinal cord injuries.
- The Central cord syndrome
Central cord syndrome is an acute cervical spinal cord injury . It was first described by Schneider in 1954.CCS has been reported to occur more frequently among older persons with cervical spondylosis, but it also may occur in younger individuals....
is associated with greater loss of upper limb function compared to lower limbs.
- The Brown-Séquard syndrome
Brown-Séquard syndrome, also known as Brown-Séquard's hemiplegia and Brown-Séquard's paralysis, is a loss of sensation and motor function that is caused by the lateral hemisection of the spinal cord...
results from injury to one side with the spinal cord, causing weakness and loss of proprioception on the side of the injury and loss of pain and thermal sensation of the other side.
- The Anterior cord syndrome
Anterior cord syndrome is a medical condition where the blood supply to the anterior portion of the spinal cord is interrupted. It is characterized by loss of motor function below the level of injury, loss of sensations carried by the anterior columns of the spinal cord , and preservation of...
results from injury to the anterior part of the spinal cord, causing weakness and loss of pain and thermal sensations below the injury site but preservation of proprioception that is usually carried in the posterior part of the spinal cord.
- Tabes Dorsalis
Tabes dorsalis is a slow degeneration of the sensory neurons that carry information. The degenerating nerves are in the dorsal columns of the spinal cord and carry information that help maintain a person's sense of position , vibration, and discriminative touch.-Cause:Tabes dorsalis is caused by...
results from injury to the posterior part of the spinal cord, usually from infection diseases such as syphilis, causing loss of touch and proprioceptive sensation.
- Conus medullaris
The conus medullaris is the terminal end of the spinal cord. It occurs near lumbar vertebral levels 1 and 2 . After the spinal cord tapers out, the spinal nerves continue as dangling nerve roots. This terminal nerve root tail is referred to as the filum terminale...
syndrome results from injury to the tip of the spinal cord, located at L1 vertebra.
- Cauda equina
The cauda equina is a structure within the lower end of the spinal column of most vertebrates, that consists of nerve roots and rootlets from above...
syndrome is, strictly speaking, not really spinal cord injury but injury to the spinal roots below the L1 vertebra.
Facts and Figures
One can have spine injury without spinal cord injury. Many people suffer transient loss of function ("stingers") in sports accidents or pain in "whiplash" of the neck without neurological loss and relatively few of these suffer spinal cord injury sufficient to warrant hospitalization. In the United States, the incidence of spinal cord injury has been estimated to be about 35 cases per million per year, or approximately 10,500 per year (35 * 300). In China, the incidence of spinal cord injury was recently estimated to be as high as 65 cases per million per year in urban areas. If so, assuming a population of 1.3 billion, this would suggest an incidence of 84,500 per year (65 * 1300).
The prevalence of spinal cord injury is not well known in many large countries. In some countries, such as Sweden and Iceland, registries are available. According to new data collected by the Christopher and Dana Reeve Foundation, in the US, there are currently 1.3 million individuals living with spinal cord injuries- a number five times that previously estimated in 2007. 61% of spinal cord injuries occur in males, and 39% in females. The average age for spinal cord injuries is 48 years old. There are many causes leading to spinal cord injuries. These include motor vehicle accidents (24%), work-related accidents (28%), sporting/recreation accidents (16%), and falls (9%).
Consequences
Divisions of Spinal Segments
 |
| Segmental Spinal Cord Level and Function |
| Level |
Function |
| Cl The cervical spinal nerve 1 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 1 .Muscles innervated by this nerve are:*Geniohyoid muscle*Rectus capitis anterior muscle...
-C6The cervical spinal nerve 6 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 6 ....
|
Neck The neck is the part of the body on many terrestrial or secondarily aquatic vertebrates that distinguishes the head from the torso or trunk. The Latin term signifying "of the neck" is cervical.-Bony anatomy: The cervical spine:...
flexors |
| Cl The cervical spinal nerve 1 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 1 .Muscles innervated by this nerve are:*Geniohyoid muscle*Rectus capitis anterior muscle...
-TlThe thoracic spinal nerve 1 is a spinal nerve of the thoracic segment..It originates from the spinal column from below the thoracic vertebra 1 ....
|
Neck The neck is the part of the body on many terrestrial or secondarily aquatic vertebrates that distinguishes the head from the torso or trunk. The Latin term signifying "of the neck" is cervical.-Bony anatomy: The cervical spine:...
extensors |
| C3 The cervical spinal nerve 3 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 3 ....
, C4The cervical spinal nerve 4 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 4 .It's control of the thoracic diaphragm has inspired a medical mnemonic: "Cut C4, breathe no more."...
, C5The cervical spinal nerve 5 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 5 ....
|
Supply diaphragm (mostly C4 The cervical spinal nerve 4 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 4 .It's control of the thoracic diaphragm has inspired a medical mnemonic: "Cut C4, breathe no more."...
) |
| C5 The cervical spinal nerve 5 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 5 ....
, C6The cervical spinal nerve 6 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 6 ....
|
ShoulderIn human anatomy, the shoulder joint comprises the part of the body where the humerus attaches to the scapula. The shoulder refers to the group of structures in the region of the joint....
movement, raise armIn anatomy, an arm is one of the upper limbs of an animal. The term arm can also be used for analogous structures, such as one of the paired upper limbs of a four-legged animal, or the arms of cephalopods....
(deltoidDeltoid can refer to:* The deltoid muscle, a muscle in the shoulder* Kite , also known as a deltoid, a type of quadrilateral* A deltoid curve, a three-sided hypocycloid* A leaf shape* The deltoid tuberosity, a part of the humerus...
); flexion of elbow (bicepsBiceps may refer to:*Biceps brachii muscle, a muscle located on the inside of the upper arm*Biceps femoris muscle, one of the hamstring muscles of the back of each thigh*Biceps , a point in a metrical pattern...
); C6The cervical spinal nerve 6 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 6 ....
externally rotates the arm (supinates) |
| C6 The cervical spinal nerve 6 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 6 ....
, C7The cervical spinal nerve 7 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 7 ....
|
Extends elbow and wrist In human anatomy, the wrist is variously defined as the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand;...
(tricepsThe triceps brachii muscle is the large muscle on the back of the human upper limb. It is the muscle principally responsible for extension of the elbow joint...
and wrist extensors); pronates wrist |
| C7 The cervical spinal nerve 7 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 7 ....
, T1The thoracic spinal nerve 1 is a spinal nerve of the thoracic segment..It originates from the spinal column from below the thoracic vertebra 1 ....
|
Flexes wrist |
| C7 The cervical spinal nerve 7 is a spinal nerve of the cervical segment..It originates from the spinal column from above the cervical vertebra 7 ....
, T1The thoracic spinal nerve 1 is a spinal nerve of the thoracic segment..It originates from the spinal column from below the thoracic vertebra 1 ....
|
Supply small muscles of the handThe hands are the two intricate, prehensile, multi-fingered body parts normally located at the end of each arm of a primate. They are the chief organs for physically manipulating the environment, used for both gross motor skills and fine motor skills...
|
| T1 The thoracic spinal nerve 1 is a spinal nerve of the thoracic segment..It originates from the spinal column from below the thoracic vertebra 1 ....
-T6The thoracic spinal nerve 6 is a spinal nerve of the thoracic segment..It originates from the spinal column from below the thoracic vertebra 6 ....
|
Intercostal Intercostal means "between the ribs". It can refer to:* Intercostal muscle* Highest intercostal vein* Intercostal arteries...
s and trunkTrunk may refer to:In biology:*Trunk, torso*Trunk, an elephant's proboscis or nose*Trunk , a tree's central superstructureIn containers:*Trunk *Trunk , a large storage compartment...
above the waistThe waist is the part of the abdomen between the rib cage and hips. On proportionate people, the waist is the narrowest part of the torso.Waistline refers to the horizontal line where the waist is narrowest, or to the general appearance of the waist...
|
| T7 The thoracic spinal nerve 7 is a spinal nerve of the thoracic segment..It originates from the spinal column from below the thoracic vertebra 7 ....
-L1The lumbar spinal nerve 1 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 1 .-Muscles:...
|
AbdominalIn vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
muscles |
| L1 The lumbar spinal nerve 1 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 1 .-Muscles:...
, L2The lumbar spinal nerve 2 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 2 .-Muscles:...
, L3The lumbar spinal nerve 3 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 3 .-Muscles:...
, L4The lumbar spinal nerve 4 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 4 .-Muscles:...
|
Thigh In humans the thigh is the area between the pelvis and the knee. Anatomically, it is part of the lower limb.The single bone in the thigh is called the femur...
flexionIn anatomy, flexion is a position that is made possible by the joint angle decreasing. The skeletal and muscular systems work together to move the joint into a "flexed" position. For example the elbow is flexed when the hand is brought closer to the shoulder...
|
| L2 The lumbar spinal nerve 2 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 2 .-Muscles:...
, L3The lumbar spinal nerve 3 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 3 .-Muscles:...
, L4The lumbar spinal nerve 4 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 4 .-Muscles:...
|
Thigh In humans the thigh is the area between the pelvis and the knee. Anatomically, it is part of the lower limb.The single bone in the thigh is called the femur...
adductionAdduction is a movement which brings a limb — arm or leg — closer to the sagittal plane of the body. It is opposed to abduction.This term is also used in reference to the operation of the muscle in anatomy or musculature.-Upper limb:* of arm at shoulder...
|
| L4 The lumbar spinal nerve 4 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 4 .-Muscles:...
, L5The lumbar spinal nerve 5 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 5 .-Muscles:...
, S1 |
Thigh In humans the thigh is the area between the pelvis and the knee. Anatomically, it is part of the lower limb.The single bone in the thigh is called the femur...
abductionStandard anatomical terms of location are employed in science which deal with the anatomy of animals to avoid ambiguities which might otherwise arise. They are not language-specific, and thus require no translation...
|
| L5 The lumbar spinal nerve 5 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 5 .-Muscles:...
, S1The sacral spinal nerve 1 is a spinal nerve of the sacral segment..It originates from the spinal column from below the 1st body of the sacrum -Muscles:...
, S2 |
Extension Extension is a movement of a joint that results in increased angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extending the flexed elbow. Straightening of the arm would...
of legŁęg may refer to the following places in Poland:*A former name for the town of Ełk *Łęg, Lower Silesian Voivodeship *Łęg, Kuyavian-Pomeranian Voivodeship *Łęg, Łódź Voivodeship...
at the hip (gluteus maximus) |
| L2 The lumbar spinal nerve 2 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 2 .-Muscles:...
, L3The lumbar spinal nerve 3 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 3 .-Muscles:...
, L4The lumbar spinal nerve 4 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 4 .-Muscles:...
|
Extension Extension is a movement of a joint that results in increased angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extending the flexed elbow. Straightening of the arm would...
of legŁęg may refer to the following places in Poland:*A former name for the town of Ełk *Łęg, Lower Silesian Voivodeship *Łęg, Kuyavian-Pomeranian Voivodeship *Łęg, Łódź Voivodeship...
at the kneeThe knee joint joins the thigh with the leg and consists of two articulations: one between the femur and tibia, and one between the femur and patella. It is the largest and most complicated joint in the human body. The knee is a mobile trocho-ginglymus , which permits flexion and extension as well...
(quadriceps femoris) |
| L4 The lumbar spinal nerve 4 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 4 .-Muscles:...
, L5The lumbar spinal nerve 5 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 5 .-Muscles:...
, S1The sacral spinal nerve 1 is a spinal nerve of the sacral segment..It originates from the spinal column from below the 1st body of the sacrum -Muscles:...
, S2The sacral spinal nerve 2 is a spinal nerve of the sacral segment..It originates from the spinal column from below the 2nd body of the sacrum -Muscles:...
|
Flexion In anatomy, flexion is a position that is made possible by the joint angle decreasing. The skeletal and muscular systems work together to move the joint into a "flexed" position. For example the elbow is flexed when the hand is brought closer to the shoulder...
of legŁęg may refer to the following places in Poland:*A former name for the town of Ełk *Łęg, Lower Silesian Voivodeship *Łęg, Kuyavian-Pomeranian Voivodeship *Łęg, Łódź Voivodeship...
at the kneeThe knee joint joins the thigh with the leg and consists of two articulations: one between the femur and tibia, and one between the femur and patella. It is the largest and most complicated joint in the human body. The knee is a mobile trocho-ginglymus , which permits flexion and extension as well...
(hamstringIn human anatomy, a hamstring is one of the three posterior thigh muscles, or to the tendons that make up the borders of the space behind the knee. In modern anatomical contexts, however, they usually refer to the posterior thigh muscles, or the tendons of the semitendinosus, the semimembranosus...
s) |
| L4 The lumbar spinal nerve 4 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 4 .-Muscles:...
, L5The lumbar spinal nerve 5 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 5 .-Muscles:...
, S1The sacral spinal nerve 1 is a spinal nerve of the sacral segment..It originates from the spinal column from below the 1st body of the sacrum -Muscles:...
|
Dorsiflexion Dorsiflexion is the movement which decreases the angle between the foot and the leg, so that the toes are brought closer to the shin. The movement moving in opposite directions is called plantarflexion.It occurs at the ankle....
of footThe foot is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion...
(tibialis anterior) |
| L4 The lumbar spinal nerve 4 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 4 .-Muscles:...
, L5The lumbar spinal nerve 5 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 5 .-Muscles:...
, S1The sacral spinal nerve 1 is a spinal nerve of the sacral segment..It originates from the spinal column from below the 1st body of the sacrum -Muscles:...
|
Extension Extension is a movement of a joint that results in increased angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extending the flexed elbow. Straightening of the arm would...
of toeToes are the digits of the foot of an animal. Animal species such as cats that walk on their toes are described as being digitigrade. Humans, and other animals that walk on the soles of their feet, are described as being plantigrade; unguligrade animals are those that walk on hooves at the tips of...
s |
| L5 The lumbar spinal nerve 5 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 5 .-Muscles:...
, S1The sacral spinal nerve 1 is a spinal nerve of the sacral segment..It originates from the spinal column from below the 1st body of the sacrum -Muscles:...
, S2The sacral spinal nerve 2 is a spinal nerve of the sacral segment..It originates from the spinal column from below the 2nd body of the sacrum -Muscles:...
|
Plantar flexion In anatomy, flexion is a position that is made possible by the joint angle decreasing. The skeletal and muscular systems work together to move the joint into a "flexed" position. For example the elbow is flexed when the hand is brought closer to the shoulder...
of footThe foot is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion...
|
| L5 The lumbar spinal nerve 5 is a spinal nerve of the lumbar segment..It originates from the spinal column from below the lumbar vertebra 5 .-Muscles:...
, S1The sacral spinal nerve 1 is a spinal nerve of the sacral segment..It originates from the spinal column from below the 1st body of the sacrum -Muscles:...
, S2The sacral spinal nerve 2 is a spinal nerve of the sacral segment..It originates from the spinal column from below the 2nd body of the sacrum -Muscles:...
|
Flexion In anatomy, flexion is a position that is made possible by the joint angle decreasing. The skeletal and muscular systems work together to move the joint into a "flexed" position. For example the elbow is flexed when the hand is brought closer to the shoulder...
of toes |
The consequences of a spinal cord injury may vary depending on the type, level, and severity of injury, but can be classified into two general categories:
- In a complete injury, function below the "neurological" level is lost. Absence of motor and sensory function below a specific spinal level is considered a "complete injury". Recent evidence suggests that less than 5% of people with "complete" spinal cord injuries recover locomotion.
- In an incomplete injury, some sensation and/or movement below the level of the injury is retained. The lowest spinal segment in humans is located at vertebral levels S4-5, corresponding to the anal sphincter and peri-anal sensation. The ability to contract the anal sphincter voluntarily
The bulbocavernosus reflex is a polysynaptic reflex that is useful in testing for spinal shock and gaining information about the state of spinal cord injuries . The test involves monitoring anal sphincter contraction in response to squeezing the glans penis or tugging on an indwelling Foley...
or to feel peri-anal pinprick or touch, the injury is considered to be "incomplete". Recent evidence suggests that over 95% of people with "incomplete" spinal cord injuries recover some locomotor function.
In addition to loss of sensation and motor function below the level of injury, individuals with spinal cord injuries will also often experience other complications:
- Bowel and bladder function is regulated by the sacral
The sacrum is a large, triangular bone at the base of the spine and at the upper and back part of the pelvic cavity, where it is inserted like a wedge between the two hip bones. Its upper part connects with the last lumbar vertebra, and bottom part with the coccyx...
region of the spine. In that regard, it is very common to experience dysfunction of the bowel and bladder, including infections of the bladder and anal incontinence, after traumatic injury.
- Sexual function is also associated with the sacral spinal segments, and is often affected after injury. During a psychogenic sexual experience, signals from the brain are sent to spinal levels T10-L2 and in case of men, are then relayed to the penis where they trigger an erection. A reflex erection, on the other hand, occurs as a result of direct physical contact to the penis or other erotic areas such as the ears, nipples or neck. A reflex erection is involuntary and can occur without sexually stimulating thoughts. The nerves that control a man’s ability to have a reflex erection are located in the sacral nerves (S2-S4) of the spinal cord and could be affected after a spinal cord injury.
- Injuries at the C-1/C-2 levels will often result in loss of breathing, necessitating mechanical ventilators or phrenic nerve pacing.
- Inability or reduced ability to regulate heart rate
Heart rate is determined by the number of heartbeats per unit of time, typically expressed as beats per minute , it can vary with as the body's need for oxygen changes, such as during exercise or sleep. The measurement of heart rate is used by medical professionals to assist in the diagnosis and...
, blood pressureBlood pressure is the pressure exerted by circulating blood on the walls of blood vessels, and is one of the principal vital signs. During each heartbeat, BP varies between a maximum and a minimum pressure...
, sweatingPerspiration is the production of a fluid, consisting primarily of water as well as various dissolved solids , that is excreted by the sweat glands in the skin of mammals...
and hence body temperature.
- Spasticity (increased reflexes and stiffness of the limbs).
- Neuropathic pain.
- Autonomic dysreflexia
Autonomic dysreflexia,"AD" or "autonomic hyperreflexia" is a condition characterized by a massive sympathetic discharge that can occur in association with spinal cord injury or disease...
or abnormal increases in blood pressure, sweating, and other autonomic responses to pain or sensory disturbances.
- Atrophy of muscle.
- Superior Mesenteric Artery Syndrome
Superior mesenteric artery syndrome is a very rare, life-threatening gastrointestinal disorder characterized by a compression of the third portion of the duodenum by the abdominal aorta and the overlying superior mesenteric artery...
.
- Osteoporosis (loss of calcium) and bone degeneration.
- Gallbladder and renal stones.
The Location of the Injury
Determining the exact level of injury is critical in making accurate predictions about the specific parts of the body that may be affected by paralysis and loss of function.
The symptoms observed after a spinal cord injury differ by location (refer to the spinal cord map on the right to determine location). Notably, while the prognosis of complete injuries are generally predictable, the symptoms of incomplete injuries span a variable range. Accordingly, it is difficult to make an accurate prognosis for these types of injuries.
Cervical injuries
Cervical (neck) injuries usually result in full or partial tetraplegia (
QuadriplegiaQuadriplegia, also known as tetraplegia, is paralysis caused by illness or injury to a human that results in the partial or total loss of use of all of their limbs and torso; paraplegia is similar but does not affect the arms...
). However, depending on the specific location and severity of trauma, limited function may be retained.
- C3 vertebrae and above : Typically results in loss of diaphragm function, necessitating the use of a ventilator for breathing.
- C4 : Results in significant loss of function at the biceps and shoulders.
- C5 : Results in potential loss of function at the shoulders and biceps, and complete loss of function at the wrists and hands.
- C6 : Results in limited wrist control, and complete loss of hand function.
- C7 and T1 : Results in lack of dexterity in the hands and fingers, but allows for limited use of arms. C7 is generally the threshold level for retaining functional independence.
Thoracic injuries
Injuries at or below the thoracic spinal levels result in
paraplegiaParaplegia is an impairment in motor and/or sensory function of the lower extremities. It is usually the result of spinal cord injury or a congenital condition such as spina bifida which affects the neural elements of the spinal canal. The area of the spinal canal which is affected in paraplegia is...
. Function of the hands, arms, neck, and breathing is usually not affected.
- T1 to T8 : Results in the inability to control the abdominal muscles. Accordingly, trunk stability is affected. The lower the level of injury, the less severe the effects.
- T9 to T12 : Results in partial loss of trunk and abdominal muscle control.
Lumbar and Sacral injuries
The effects of injuries to the
lumbarIn anatomy, lumbar is an adjective that means of or pertaining to the abdominal segment of the torso, between the diaphragm and the sacrum . The lumbar region is sometimes referred to as the lower spine...
or
sacralSacral may refer to:*sacred*sacrum...
regions of the spinal cord are decreased control of the
legAlthough in common usage, the human leg or leg can refer to the entire lower extremity or limb of the human body, including the foot, thigh and even the hip or gluteal region, the precise definition in human anatomy refers to the section of the lower limb extending between the knee and the...
s and hips, urinary system, and anus.
Central Cord and Other Syndromes
Central cord syndromeCentral cord syndrome is an acute cervical spinal cord injury . It was first described by Schneider in 1954.CCS has been reported to occur more frequently among older persons with cervical spondylosis, but it also may occur in younger individuals....
(picture 1) is a form of incomplete spinal cord injury characterized by impairment in the arms and hands and, to a lesser extent, in the legs. This is also referred to as inverse paraplegia, because the hands and arms are paralyzed while the legs and lower extremities work correctly.
Most often the damage is to the cervical or upper thoracic regions of the spinal cord, and characterized by weakness in the arms with relative sparing of the legs with variable sensory loss.
This condition is associated with ischemia, hemorrhage, or necrosis involving the central portions of the spinal cord (the large nerve fibers that carry information directly from the cerebral cortex). Corticospinal fibers destined for the legs are spared due to their more external location in the spinal cord.
This clinical pattern may emerge during recovery from spinal shock due to prolonged swelling around or near the vertebrae, causing pressures on the cord. The symptoms may be transient or permanent.
Anterior cord syndromeAnterior cord syndrome is a medical condition where the blood supply to the anterior portion of the spinal cord is interrupted. It is characterized by loss of motor function below the level of injury, loss of sensations carried by the anterior columns of the spinal cord , and preservation of...
(picture 2) is also an incomplete spinal cord injury. Below the injury, motor function, pain sensation, and temperature sensation is lost; touch, proprioception (sense of position in space), and vibration sense remain intact.
Posterior cord syndromePosterior cord syndrome is a condition caused by lesion of the posterior portion of the spinal cord. It can be caused by an interruption to the posterior spinal artery.Unlike anterior cord syndrome, it is a very rare condition....
(not pictured) can also occur, but is very rare.
Brown-Séquard syndromeBrown-Séquard syndrome, also known as Brown-Séquard's hemiplegia and Brown-Séquard's paralysis, is a loss of sensation and motor function that is caused by the lateral hemisection of the spinal cord...
(picture 3) usually occurs when the spinal cord is hemisectioned or injured on the lateral side. On the ipsilateral side of the injury (same side), there is a loss of motor function, proprioception, vibration, and light touch. Contralaterally (opposite side of injury), there is a loss of pain, temperature, and deep touch sensations
Potential Treatments
Treatment options for acute, traumatic non-penetrating spinal cord injuries include the administration of a high dose of an anti-inflammatory agent,
methylprednisoloneMethylprednisolone is a synthetic glucocorticoid drug. It is sold in the USA and Canada under the brand names Phocenta, Medrol, Solu-Medrol and Cadista. It is also available as a generic drug....
, within 8 hours of injury. This recommendation is primarily based on the National Acute Spinal Cord Injury Studies (NASCIS) I and II. However, in a third study, methylprednisolone failed to demonstrate an effect in comparison to
placeboA placebo is a sham medical intervention. In one common placebo procedure, a patient is given an inert sugar pill, told that it may improve his/her condition, but not told that it is in fact inert...
. Additionally, due to increased risk of infections, the use of this anti-inflammatory drug after spinal cord injuries is no longer recommended . Presently, administration of cold saline acutely after injury is gaining popularity, but there is a paucity of empirical evidence for the beneficial effects of
therapeutic hypothermiaTherapeutic hypothermia is a medical treatment that lowers a patient's body temperature in order to help reduce the risk of the ischemic injury to tissue following a period of insufficient blood flow. Periods of insufficient blood flow may be due to cardiac arrest or the occlusion of an artery by...
.
Scientists are investigating many promising avenues for treatment of spinal cord injury. Numerous articles in the medical literature describe research, mostly in animal models, aimed at reducing the paralyzing effects of injury and promoting regrowth of functional nerve fibers. Despite the devastating effects of the condition, commercial funding for research investigating a cure after spinal cord injury is limited, partially due to the small size of the population of potential beneficiaries. Despite this limitation, a number of experimental treatments have reached controlled human trials . In addition, therapeutic strategies involving neuronal protection and regeneration are also being investigated in other
neurodegenerative diseaseNeurodegenerative disease is a condition in which cells of the brain and spinal cord are lost. The brain and spinal cord are composed of neurons that perform different functions such as controlling movements, processing sensory information, and making decisions...
s such as
Alzheimer's DiseaseAlzheimer's disease , also called Alzheimer disease, Senile Dementia of the Alzheimer Type or simply Alzheimer's, is the most common form of dementia. This incurable, degenerative, and terminal disease was first described by German psychiatrist and neuropathologist Alois Alzheimer in 1906 and was...
,
Parkinson's DiseaseParkinson's disease is a degenerative disorder of the central nervous system that often impairs the sufferer's motor skills, speech, and other functions....
,
Amyotrophic Lateral SclerosisAmyotrophic lateral sclerosis is a form of motor neuron disease. ALS, sometimes called Maladie de Charcot, is a progressive, fatal, neurodegenerative disease caused by the degeneration of motor neurons, the nerve cells in the central nervous system that control voluntary muscle movement...
and
Multiple sclerosisMultiple sclerosis is an idiopathic disease of suspected autoimmune cause, in which the body's immune response attacks a person's central nervous system , leading to demyelination. Disease onset usually occurs in young adults, and it is more common in females...
. There are many similarities between these conditions of the CNS and spinal cord injuries, thus increasing the potential for discovery of a treatment after spinal cord injuries.
Advances in identification of an effective therapeutic target after spinal cord injury have been newsworthy, and considerable media attention is often drawn towards new developments in this area. However, aside from methylprednisolone, none of these developments have reached even limited use in the clinical care of human spinal cord injury in the U.S. . Around the world, proprietary centers offering
stem cellStem cells are cells found in most, if not all, multi-cellular organisms. They are characterized by the ability to renew themselves through mitotic cell division and differentiating into a diverse range of specialized cell types. Research in the stem cell field grew out of findings by Canadian...
transplants and treatment with neuroregenerative substances are fueled by glowing testimonial reports of neurological improvement. Independent validation of the results of these treatments is lacking. However, in January 2009, the Geron Corporation received FDA clearance to begin human safety testing of its stem cell treatment candidate, GRNOPC1, on newly injured patients with complete thoracic injury. A diverse array of other treatments are being researched, including biomaterial solutions, cell replacement therapies, and electronic stimulative devices.
External links