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162-402: A spinal cord injury ( SCI ) is damage to the spinal cord that causes temporary or permanent changes in its function. It is a destructive neurological and pathological state that causes major motor, sensory and autonomic dysfunctions. Symptoms of spinal cord injury may include loss of muscle function, sensation , or autonomic function in the parts of the body served by the spinal cord below

324-556: A pulmonary embolism , lodging in the lung and cutting off blood supply to it. DVT is an especially high risk in SCI, particularly within 10 days of injury, occurring in over 13% in the acute care setting. Preventative measures include anticoagulants , pressure hose, and moving the patient's limbs. The usual signs and symptoms of DVT and pulmonary embolism may be masked in SCI cases due to effects such as alterations in pain perception and nervous system functioning. Urinary tract infection (UTI)

486-409: A cervical rib can develop from C7 as an anatomical variation . The term cervicothoracic is often used to refer to the cervical and thoracic vertebrae together, and sometimes also their surrounding areas. The twelve thoracic vertebrae and their transverse processes have surfaces that articulate with the ribs . Some rotation can occur between the thoracic vertebrae, but their connection with

648-408: A SCI may need to wait if emergency surgery is needed to stabilize other life-threatening injuries. Acute SCI merits treatment in an intensive care unit , especially injuries to the cervical spinal cord. People with SCI need repeated neurological assessments and treatment by neurosurgeons. People should be removed from the spine board as rapidly as possible to prevent complications from its use. If

810-403: A broad plate, a lamina , projects backward and medially to join and complete the vertebral arch and form the posterior border of the vertebral foramen, which completes the triangle of the vertebral foramen. The upper surfaces of the laminae are rough to give attachment to the ligamenta flava . These ligaments connect the laminae of adjacent vertebra along the length of the spine from the level of

972-418: A day. Priapism , an erection of the penis may be a sign of acute spinal cord injury. The specific parts of the body affected by loss of function are determined by the level of injury. Some signs, such as bowel and bladder dysfunction can occur at any level. Neurogenic bladder involves a compromised ability to empty the bladder and is a common symptom of spinal cord injury. This can lead to high pressures in

1134-453: A facet on each side of the vertebral body, which articulates with the head of a rib . There is also a facet on each of the transverse processes which articulates with the tubercle of a rib . The number of thoracic vertebrae varies considerably across the species. Most marsupials have thirteen, but koalas only have eleven. The usual number is twelve to fifteen in mammals , (twelve in the human ), though there are from eighteen to twenty in

1296-409: A high SCI risk. Since head and spinal trauma frequently coexist, anyone who is unconscious or has a lowered level of consciousness as a result of a head injury is spinal motion restricted. A rigid cervical collar is applied to the neck, and the head is held with blocks on either side and the person is strapped to a backboard . Extrication devices are used to move people without excessively moving

1458-413: A human spinal cord: In the fetus, vertebral segments correspond with spinal cord segments. However, because the vertebral column grows longer than the spinal cord, spinal cord segments do not correspond to vertebral segments in the adult, particularly in the lower spinal cord. For example, lumbar and sacral spinal cord segments are found between vertebral levels T9 and L2, and the spinal cord ends around

1620-433: A large range of motion. The atlanto-occipital joint allows the skull to move up and down, while the atlanto-axial joint allows the upper neck to twist left and right. The axis also sits upon the first intervertebral disc of the spinal column. Cervical vertebrae possess transverse foramina to allow for the vertebral arteries to pass through on their way to the foramen magnum to end in the circle of Willis . These are

1782-401: A lateral costiform process , a mammillary process and an accessory process . The superior, or upper tubercle is the mammillary process which connects with the superior articular process. The multifidus muscle attaches to the mammillary process and this muscle extends through the length of the vertebral column, giving support. The inferior, or lower tubercle is the accessory process and this

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1944-532: A lesion below the level at which the spinal cord ends. Descending nerve roots continue as the cauda equina at levels L2–S5 below the conus medullaris before exiting through intervertebral foraminae. Thus it is not a true spinal cord syndrome since it is nerve roots that are damaged and not the cord itself; however, it is common for several of these nerves to be damaged at the same time due to their proximity. CES can occur by itself or alongside conus medullaris syndrome. It can cause low back pain, weakness or paralysis in

2106-539: A loss of muscle tone due to disuse of the muscles below the injured site. The two areas of the spinal cord most commonly injured are the cervical spine (C1–C7) and the lumbar spine (L1–L5). (The notation C1, C7, L1, L5 refer to the location of a specific vertebra in either the cervical, thoracic, or lumbar region of the spine.) Spinal cord injury can also be non-traumatic and caused by disease ( transverse myelitis , polio , spina bifida , Friedreich's ataxia , spinal cord tumor , spinal stenosis etc.) Globally, it

2268-456: A posterior arch and two lateral masses. At the outside centre points of both arches there is a tubercle, an anterior tubercle and a posterior tubercle , for the attachment of muscles. The front surface of the anterior arch is convex and its anterior tubercle gives attachment to the longus colli muscle . The posterior tubercle is a rudimentary spinous process and gives attachment to the rectus capitis posterior minor muscle . The spinous process

2430-453: A result of arthritis . Another condition is spondylolisthesis when one vertebra slips forward onto another. The reverse of this condition is retrolisthesis where one vertebra slips backward onto another. The vertebral pedicle is often used as a radiographic marker and entry point in vertebroplasty , kyphoplasty , and spinal fusion procedures. The arcuate foramen is a common anatomical variation more frequently seen in females. It

2592-444: A result of injury, 26.82% In some countries falls are more common, even surpassing vehicle crashes as the leading cause of SCI. The rates of violence-related SCI depend heavily on place and time. Of all sports-related SCIs, shallow water dives are the most common cause; winter sports and water sports have been increasing as causes while association football and trampoline injuries have been declining. Hanging can cause injury to

2754-488: A scale of 0–2: 0 is no sensation, 1 is altered or decreased sensation, and 2 is full sensation. Each side of the body is graded independently. In a "complete" spinal injury, all functions below the injured area are lost, whether or not the spinal cord is severed. An "incomplete" spinal cord injury involves preservation of motor or sensory function below the level of injury in the spinal cord. To be classed as incomplete, there must be some preservation of sensation or motion in

2916-405: A specific part of the spine is called a myotome , and injury to that part of the spinal cord can cause problems with movements that involve those muscles. The muscles may contract uncontrollably ( spasticity ), become weak , or be completely paralysed . Spinal shock , loss of neural activity including reflexes below the level of injury, occurs shortly after the injury and usually goes away within

3078-435: A spinal cord injury. The features are namely paralysis, sensory loss, or both at any level. Other symptoms may include incontinence. A radiographic evaluation using an X-ray , CT scan, or MRI can determine if there is damage to the spinal column and where it is located. X-rays are commonly available and can detect instability or misalignment of the spinal column, but do not give very detailed images and can miss injuries to

3240-427: A strong pillar of support for the body. There are seven processes projecting from the vertebra: A major part of a vertebra is a backward extending spinous process (sometimes called the neural spine) which projects centrally. This process points dorsally and caudally from the junction of the laminae. The spinous process serves to attach muscles and ligaments . The two transverse processes, one on each side of

3402-533: A victim might only suffer loss of hand or foot function. More severe injuries may result in paraplegia , tetraplegia (also known as quadriplegia), or full body paralysis below the site of injury to the spinal cord. Damage to upper motor neuron axons in the spinal cord results in a characteristic pattern of ipsilateral deficits. These include hyperreflexia , hypertonia and muscle weakness. Lower motor neuronal damage results in its own characteristic pattern of deficits. Rather than an entire side of deficits, there

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3564-573: Is neurogenic shock , which results from an interruption in output from the sympathetic nervous system responsible for maintaining muscle tone in the blood vessels. Without the sympathetic input, the vessels relax and dilate. Neurogenic shock presents with dangerously low blood pressure, low heart rate , and blood pooling in the limbs—which results in insufficient blood flow to the spinal cord and potentially further damage to it. Complications of spinal cord injuries include pulmonary edema , respiratory failure , neurogenic shock , and paralysis below

3726-419: Is a bony bridge found on the first cervical vertebra, the atlas where it covers the groove for the vertebral artery . Degenerative disc disease is a condition usually associated with ageing in which one or more discs degenerate. This can often be a painfree condition but can also be very painful. In other animals, the vertebrae take the same regional names except for the coccygeal – in animals with tails,

3888-430: Is a pattern relating to the myotome affected by the damage. Additionally, lower motor neurons are characterized by muscle weakness, hypotonia , hyporeflexia and muscle atrophy . Spinal shock and neurogenic shock can occur from a spinal injury. Spinal shock is usually temporary, lasting only for 24–48 hours, and is a temporary absence of sensory and motor functions. Neurogenic shock lasts for weeks and can lead to

4050-406: Is a surgical operation to remove the laminae in order to access the spinal canal. The removal of just part of a lamina is called a laminotomy . A pinched nerve caused by pressure from a disc, vertebra or scar tissue might be remedied by a foraminotomy to broaden the intervertebral foramina and relieve pressure. It can also be caused by a foramina stenosis , a narrowing of the nerve opening, as

4212-412: Is also the location of groups of spinal interneurons that make up the neural circuits known as central pattern generators . These circuits are responsible for controlling motor instructions for rhythmic movements such as walking. A congenital disorder is diastematomyelia in which part of the spinal cord is split usually at the level of the upper lumbar vertebrae. Sometimes the split can be along

4374-414: Is an irregular bone with a complex structure composed of bone and some hyaline cartilage , that make up the vertebral column or spine, of vertebrates . The proportions of the vertebrae differ according to their spinal segment and the particular species. The basic configuration of a vertebra varies; the bone is the body, and the central part of the body is the centrum. The upper and lower surfaces of

4536-790: Is an injury to the end of the spinal cord the conus medullaris , located at about the T12–L2 vertebrae in adults. This region contains the S4–S5 spinal segments, responsible for bowel, bladder, and some sexual functions , so these can be disrupted in this type of injury. In addition, sensation and the Achilles reflex can be disrupted. Causes include tumors , physical trauma, and ischemia . Cauda equina syndrome may also be caused by central disc prolapse or slipped disc, infections such as epidural abscess, spinal haemorrhages, secondary to medical procedures and birth abnormalities. Cauda equina syndrome (CES) results from

4698-436: Is another risk that may not display the usual symptoms (pain, urgency, and frequency); it may instead be associated with worsened spasticity. The risk of UTI, likely the most common complication in the long term, is heightened by use of indwelling urinary catheters . Catheterization may be necessary because SCI interferes with the bladder's ability to empty when it gets too full, which could trigger autonomic dysreflexia or damage

4860-413: Is around 45 cm (18 in) long in adult men and around 43 cm (17 in) long in adult women. The diameter of the spinal cord ranges from 13 mm ( 1 ⁄ 2  in) in the cervical and lumbar regions to 6.4 mm ( 1 ⁄ 4  in) in the thoracic area. The spinal cord functions primarily in the transmission of nerve signals from the motor cortex to the body, and from

5022-402: Is called a dermatome , and injury to that part of the spine can cause pain, numbness, or a loss of sensation in the related areas. Paraesthesia , a tingling or burning sensation in affected areas of the skin, is another symptom. A person with a lowered level of consciousness may show a response to a painful stimulus above a certain point but not below it. A group of muscles innervated through

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5184-414: Is defined as the lowest level of full sensation and function. Paraplegia occurs when the legs are affected by the spinal cord damage (in thoracic, lumbar, or sacral injuries), and tetraplegia occurs when all four limbs are affected (cervical damage). SCI is also classified by the degree of impairment. The International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI), published by

5346-440: Is due to the difference in thickness between the front and back parts of the intervertebral discs. The lumbar vertebrae are located between the ribcage and the pelvis and are the largest of the vertebrae. The pedicles are strong, as are the laminae, and the spinous process is thick and broad. The vertebral foramen is large and triangular. The transverse processes are long and narrow and three tubercles can be seen on them. These are

5508-451: Is enlarged in the cervical and lumbar regions. The cervical enlargement, stretching from the C4 to T1 vertebrae, is where sensory input comes from and motor output goes to the arms and trunk. The lumbar enlargement, located between T10 and L1, handles sensory input and motor output coming from and going to the legs. The spinal cord is continuous with the caudal portion of the medulla , running from

5670-533: Is expected there are around 40 to 80 cases of spinal cord injury per million population, and approximately 90% of these cases result from traumatic events. Real or suspected spinal cord injuries need immediate immobilisation including that of the head. Scans will be needed to assess the injury. A steroid, methylprednisolone , can be of help as can physical therapy and possibly antioxidants . Treatments need to focus on limiting post-injury cell death, promoting cell regeneration, and replacing lost cells. Regeneration

5832-630: Is facilitated by maintaining electric transmission in neural elements. Spinal stenoses at the lumbar region are usually due to disc herniation , hypertrophy of the facet joint and ligamentum flavum , osteophyte , and spondylolisthesis . An uncommon cause of lumbar spinal stenosis is spinal epidural lipomatosis , a condition where there is excessive deposit of fat in the epidural space, causing compression of nerve root and spinal cord. The epidural fat can be seen as low density on CT scan and high intensity on T2-weighted fast spin echo MRI images. Vertebra Each vertebra ( pl. : vertebrae )

5994-416: Is found at the back part of the base of the transverse process. The term lumbosacral is often used to refer to the lumbar and sacral vertebrae together, and sometimes includes their surrounding areas. There are five sacral vertebrae (S1–S5) which are fused in maturity, into one large bone, the sacrum , with no intervertebral discs . The sacrum with the ilium forms a sacroiliac joint on each side of

6156-477: Is inadequate to maintain the spinal cord beyond the cervical segments. The major contribution to the arterial blood supply of the spinal cord below the cervical region comes from the radially arranged posterior and anterior radicular arteries , which run into the spinal cord alongside the dorsal and ventral nerve roots, but with one exception do not connect directly with any of the three longitudinal arteries. These intercostal and lumbar radicular arteries arise from

6318-417: Is ipsilateral hemiplegia. Spinothalamic tracts are in charge for pain and temperature sensation and because these tracts cross to the opposite side and above the spinal cord there is loss on the contralateral side. Posterior spinal artery syndrome (PSAS), in which just the dorsal columns of the spinal cord are affected, is usually seen in cases of chronic myelopathy but can also occur with infarction of

6480-405: Is known as the cuneocerebellar tract . The descending tracts are of motor information. Descending tracts involve two neurons: the upper motor neuron, and lower motor neuron. A nerve signal travels down the upper motor neuron until it synapses with the lower motor neuron in the spinal cord. Then, the lower motor neuron conducts the nerve signal to the spinal root where efferent nerve fibers carry

6642-431: Is necessary for the correct assembly of the nervous system. Overall, spontaneous embryonic activity has been shown to play a role in neuron and muscle development but is probably not involved in the initial formation of connections between spinal neurons. The spinal cord mainly functions to carry information to and from the brain, in ascending and descending tracts. There are two ascending somatosensory pathways in

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6804-488: Is pain, including nociceptive pain (indication of potential or actual tissue damage) and neuropathic pain , when nerves affected by damage convey erroneous pain signals in the absence of noxious stimuli. Spasticity , the uncontrollable tensing of muscles below the level of injury, occurs in 65–78% of chronic SCI. It results from lack of input from the brain that quells muscle responses to stretch reflexes. It can be treated with drugs and physical therapy. Spasticity increases

6966-400: Is present but there is no evidence of spinal column injury on radiographs . Spinal column injury is trauma that causes fracture of the bone or instability of the ligaments in the spine ; this can coexist with or cause injury to the spinal cord, but each injury can occur without the other. Abnormalities might show up on magnetic resonance imaging (MRI), but the term was coined before MRI

7128-443: Is preserved in the sacral dermatomes, even though sensation may be more impaired in other, higher dermatomes below the level of the lesion. Sacral sparing has been attributed to the fact that the sacral spinal pathways are not as likely as the other spinal pathways to become compressed after injury due to the lamination of fibers within the spinal cord. Spinal cord injury without radiographic abnormality exists when spinal cord injury

7290-400: Is prevented with measures including societal and individual efforts to reduce driving under the influence of drugs or alcohol, distracted driving , and drowsy driving . Other efforts include increasing road safety (such as marking hazards and adding lighting) and vehicle safety, both to prevent accidents, such as routine maintenance and antilock brakes . There are also approaches mitigate

7452-417: Is small so as not to interfere with the movement between the atlas and the skull . On the under surface is a facet for articulation with the dens of the axis. Specific to the cervical vertebra is the transverse foramen (also known as foramen transversarium ). This is an opening on each of the transverse processes which gives passage to the vertebral artery and vein and a sympathetic nerve plexus . On

7614-537: Is the groove in the ventral side. The human spinal cord is divided into segments where pairs of spinal nerves (mixed; sensory and motor) form. Six to eight motor nerve rootlets branch out of right and left ventralateral sulci in a very orderly manner. Nerve rootlets combine to form nerve roots. Likewise, sensory nerve rootlets form off right and left dorsal lateral sulci and form sensory nerve roots. The ventral (motor) and dorsal (sensory) roots combine to form spinal nerves (mixed; motor and sensory), one on each side of

7776-504: Is the main pathway for information connecting the brain and peripheral nervous system . Much shorter than its protecting spinal column, the human spinal cord originates in the brainstem, passes through the foramen magnum , and continues through to the conus medullaris near the second lumbar vertebra before terminating in a fibrous extension known as the filum terminale . It is about 45 centimetres (18 inches) long in males and about 43 cm (17 in) in females, ovoid -shaped, and

7938-442: Is the spongy type of osseous tissue , whose microanatomy has been specifically studied within the pedicle bones. This cancellous bone is in turn, covered by a thin coating of cortical bone (or compact bone), the hard and dense type of osseous tissue. The vertebral arch and processes have thicker coverings of cortical bone. The upper and lower surfaces of the body of the vertebra are flattened and rough in order to give attachment to

8100-434: Is typically based on symptoms and medical imaging . Efforts to prevent SCI include individual measures such as using safety equipment, societal measures such as safety regulations in sports and traffic, and improvements to equipment. Treatment starts with restricting further motion of the spine and maintaining adequate blood pressure . Corticosteroids have not been found to be useful. Other interventions vary depending on

8262-429: Is used to determine the level and severity of injury. The first stage in the management of a suspected spinal cord injury is geared toward basic life support and preventing further injury: maintaining airway, breathing, circulation, and restricting further motion of the spine. In the emergency setting, most people who has been subjected to forces strong enough to cause SCI are treated as though they have instability in

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8424-480: The American Spinal Injury Association (ASIA), is widely used to document sensory and motor impairments following SCI. It is based on neurological responses, touch and pinprick sensations tested in each dermatome, and strength of the muscles that control key motions on both sides of the body. Muscle strength is scored on a scale of 0–5 according to the table on the right, and sensation is graded on

8586-453: The afferent fibers of the sensory neurons to the sensory cortex . It is also a center for coordinating many reflexes and contains reflex arcs that can independently control reflexes. It is also the location of groups of spinal interneurons that make up the neural circuits known as central pattern generators . These circuits are responsible for controlling motor instructions for rhythmic movements such as walking. The spinal cord

8748-497: The cervical vertebrae bear ribs. In many groups, such as lizards and saurischian dinosaurs, the cervical ribs are large; in birds, they are small and completely fused to the vertebrae. The transverse processes of mammals are homologous to the cervical ribs of other amniotes . In the whale, the cervical vertebrae are typically fused, an adaptation trading flexibility for stability during swimming. All mammals except manatees and sloths have seven cervical vertebrae, whatever

8910-588: The horse , tapir , rhinoceros and elephant . In certain sloths, there is an extreme number of twenty-five and at the other end only nine in the cetacean . There are fewer lumbar vertebrae in chimpanzees and gorillas , which have three in contrast to the five in the genus Homo . This reduction in number gives an inability of the lumbar spine to lordose but gives an anatomy that favours vertical climbing, and hanging ability more suited to feeding locations in high-canopied regions. The bonobo differs by having four lumbar vertebrae. Caudal vertebrae are

9072-420: The intervertebral discs . These surfaces are the vertebral endplates which are in direct contact with the intervertebral discs and form the joint. The endplates are formed from a thickened layer of the cancellous bone of the vertebral body, the top layer being more dense. The endplates function to contain the adjacent discs, to evenly spread the applied loads, and to provide anchorage for the collagen fibers of

9234-412: The pelvis , which articulates with the hips . The last three to five coccygeal vertebrae (but usually four) (Co1–Co5) make up the tailbone or coccyx . There are no intervertebral discs . Somites form in the early embryo and some of these develop into sclerotomes. The sclerotomes form the vertebrae as well as the rib cartilage and part of the occipital bone . From their initial location within

9396-501: The posterior spinal artery . This rare syndrome causes the loss of proprioception and sense of vibration below the level of injury while motor function and sensation of pain, temperature, and touch remain intact. Usually posterior cord injuries result from insults like disease or vitamin deficiency rather than trauma. Tabes dorsalis , due to injury to the posterior part of the spinal cord caused by syphilis, results in loss of touch and proprioceptive sensation. Conus medullaris syndrome

9558-400: The rib cage prevents much flexion or other movement. They may also be known as "dorsal vertebrae" in the human context. The vertebral bodies are roughly heart-shaped and are about as wide anterio-posteriorly as they are in the transverse dimension. Vertebral foramina are roughly circular in shape. The top surface of the first thoracic vertebra has a hook-shaped uncinate process, just like

9720-484: The sacral region. It is common to experience sexual dysfunction after injury , as well as dysfunction of the bowel and bladder, including fecal and urinary incontinence . In addition to the problems found in lower-level injuries, thorax (chest height) spinal lesions can affect the muscles in the trunk. Injuries at the level of T1 to T8 result in inability to control the abdominal muscles. Trunk stability may be affected; even more so in higher level injuries. The lower

9882-547: The sacrum and four coccygeal vertebrae , forming the coccyx . Excluding rare deviations, the total number of vertebrae ranges from 32 to 35. In about 10% of people, both the total number of pre-sacral vertebrae and the number of vertebrae in individual parts of the spine can vary. The most frequent deviations are eleven (rarely thirteen) thoracic vertebrae, four or six lumbar vertebrae and three or five coccygeal vertebrae (rarely up to seven). The regional vertebrae increase in size as they progress downward but become smaller in

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10044-439: The second cervical vertebra . Above and below the pedicles are shallow depressions called vertebral notches ( superior and inferior ). When the vertebrae articulate the notches align with those on adjacent vertebrae and these form the openings of the intervertebral foramina . The foramina allow the entry and exit of the spinal nerves from each vertebra, together with associated blood vessels. The articulating vertebrae provide

10206-462: The superior cerebellar peduncle where they decussate again. From here, the information is brought to deep nuclei of the cerebellum including the fastigial and interposed nuclei . From the levels of L2 to T1, proprioceptive information enters the spinal cord and ascends ipsilaterally, where it synapses in Clarke's nucleus . The secondary neuronal axons continue to ascend ipsilaterally and then pass into

10368-483: The systolic blood pressure falls below 90 mmHg within days of the injury, blood supply to the spinal cord may be reduced, resulting in further damage. Thus it is important to maintain the blood pressure which may be done using intravenous fluids and vasopressors . Vasopressors used include phenylephrine , dopamine , or norepinephrine . Mean arterial blood pressure is measured and kept at 85 to 90 mmHg for seven days after injury. Spinal cord In humans ,

10530-603: The vestibulospinal tract , the tectospinal tract and the reticulospinal tract . The rubrospinal tract descends with the lateral corticospinal tract, and the remaining three descend with the anterior corticospinal tract. The function of lower motor neurons can be divided into two different groups: the lateral corticospinal tract and the anterior cortical spinal tract. The lateral tract contains upper motor neuronal axons which synapse on dorsal lateral (DL) lower motor neurons. The DL neurons are involved in distal limb control. Therefore, these DL neurons are found specifically only in

10692-498: The L1/L2 vertebral level, forming a structure known as the conus medullaris. Although the spinal cord cell bodies end around the L1/L2 vertebral level, the spinal nerves for each segment exit at the level of the corresponding vertebra. For the nerves of the lower spinal cord, this means that they exit the vertebral column much lower (more caudally) than their roots. As these nerves travel from their respective roots to their point of exit from

10854-550: The T11 spinal segment is located higher than the T11 bony vertebra, and the sacral spinal cord segment is higher than the L1 vertebral body. The grey columns , (three regions of grey matter) in the center of the cord, is shaped like a butterfly and consists of cell bodies of interneurons , motor neurons, neuroglia cells and unmyelinated axons. The anterior and posterior grey columns present as projections of grey matter and are also known as

11016-474: The U.S., motor vehicle accidents are the most common cause of SCIs; second are falls , then violence such as gunshot wounds, then sports injuries . Another study from Asia, found that the most common cause of the SCI is fall (31.70%) from various sites such as fall from roof-tops (9.75%), electric pole (7.31%), fall from tree (7.31%) etc. Whereas road traffic accidents count for 19.51%, firearm injuries (12.19%), slipped foot (7.31%) and sports injuries (4.87%). As

11178-409: The adjoining lumbar section. The five lumbar vertebrae are the largest of the vertebrae, their robust construction being necessary for supporting greater weight than the other vertebrae. They allow significant flexion , extension and moderate lateral flexion (side-bending). The discs between these vertebrae create a natural lumbar lordosis (a spinal curvature that is concave posteriorly). This

11340-534: The anterior column but do not synapse across the anterior white commissure. Rather, they only synapse on VM lower motor neurons ipsilaterally. The VM lower motor neurons control the large, postural muscles of the axial skeleton . These lower motor neurons, unlike those of the DL, are located in the ventral horn all the way throughout the spinal cord. The spinal cord is a center for coordinating many reflexes and contains reflex arcs that can independently control reflexes. It

11502-400: The aorta for example during aortic aneurysm repair, can result in spinal cord infarction and paraplegia. The spinal cord is made from part of the neural tube during development. There are four stages of the spinal cord that arises from the neural tube: The neural plate, neural fold, neural tube, and the spinal cord. Neural differentiation occurs within the spinal cord portion of the tube. As

11664-461: The aorta, provide major anastomoses and supplement the blood flow to the spinal cord. In humans the largest of the anterior radicular arteries is known as the artery of Adamkiewicz , or anterior radicularis magna (ARM) artery, which usually arises between L1 and L2, but can arise anywhere from T9 to L5. Impaired blood flow through these critical radicular arteries, especially during surgical procedures that involve abrupt disruption of blood flow through

11826-430: The arachnoid and the underlying pia mater is called the subarachnoid space . The subarachnoid space contains cerebrospinal fluid , which can be sampled with a lumbar puncture , or "spinal tap" procedure. The delicate pia mater, the innermost protective layer, is tightly associated with the surface of the spinal cord. The cord is stabilized within the dura mater by the connecting denticulate ligaments , which extend from

11988-403: The areas innervated by S4 to S5, including voluntary external anal sphincter contraction. The nerves in this area are connected to the very lowest region of the spinal cord, and retaining sensation and function in these parts of the body indicates that the spinal cord is only partially damaged. Incomplete injury by definition includes a phenomenon known as sacral sparing: some degree of sensation

12150-437: The areas supplied by the affected level of the spinal cord. Congenital conditions and tumors that compress the cord can also cause SCI, as can vertebral spondylosis and ischemia . Multiple sclerosis is a disease that can damage the spinal cord, as can infectious or inflammatory conditions such as tuberculosis , herpes zoster or herpes simplex , meningitis , myelitis , and syphilis . Vehicle-related spinal cord injury

12312-494: The base of the skull to the body of the first lumbar vertebra. It does not run the full length of the vertebral column in adults. It is made of 31 segments from which branch one pair of sensory nerve roots and one pair of motor nerve roots. The nerve roots then merge into bilaterally symmetrical pairs of spinal nerves . The peripheral nervous system is made up of these spinal roots, nerves, and ganglia . The dorsal roots are afferent fascicles , receiving sensory information from

12474-413: The bladder permanently. The use of intermittent catheterization to empty the bladder at regular intervals throughout the day has decreased the mortality due to kidney failure from UTI in the first world, but it is still a serious problem in developing countries. An estimated 24–45% of people with spinal cord injuries have major depressive disorder , and the suicide rate is as much as six times that of

12636-423: The bladder that can damage the kidneys. Spinal cord injuries at the cervical vertebrae (neck) level result in full or partial tetraplegia , also called quadriplegia. Depending on the specific location and severity of trauma, limited function may be retained. Additional symptoms of cervical injuries include low heart rate , low blood pressure , problems regulating body temperature , and breathing dysfunction. If

12798-417: The canal. The dura mater is the outermost layer, and it forms a tough protective coating. Between the dura mater and the surrounding bone of the vertebrae is a space called the epidural space . The epidural space is filled with adipose tissue , and it contains a network of blood vessels . The arachnoid mater , the middle protective layer, is named for its open, spiderweb-like appearance. The space between

12960-412: The case of multiple or massive trauma, some of it reflects the failure to adequately restrict motion of the spine. SCI can impair the body's ability to keep warm, so warming blankets may be needed. Initial care in the hospital, as in the prehospital setting, aims to ensure adequate airway, breathing, cardiovascular function, and spinal motion restriction. Imaging of the spine to determine the presence of

13122-457: The cell death that occurs immediately in the original injury, and biochemical cascades that are initiated by the original insult and cause further tissue damage. These secondary injury pathways include the ischemic cascade , inflammation , swelling , cell suicide , and neurotransmitter imbalances. They can take place for minutes or weeks following the injury. At each level of the spinal column, spinal nerves branch off from either side of

13284-423: The cerebellum via the inferior cerebellar peduncle . This tract is known as the dorsal spinocerebellar tract. From above T1, proprioceptive primary axons enter the spinal cord and ascend ipsilaterally until reaching the accessory cuneate nucleus , where they synapse. The secondary axons pass into the cerebellum via the inferior cerebellar peduncle where again, these axons synapse on cerebellar deep nuclei. This tract

13446-564: The cervical and lumbosacral enlargements within the spinal cord. There is no decussation in the lateral corticospinal tract after the decussation at the medullary pyramids. The anterior corticospinal tract descends ipsilaterally in the anterior column, where the axons emerge and either synapse on lower ventromedial (VM) motor neurons in the ventral horn ipsilaterally or descussate at the anterior white commissure where they synapse on VM lower motor neurons contralaterally . The tectospinal, vestibulospinal and reticulospinal descend ipsilaterally in

13608-417: The cervical spine, as may occur in attempted suicide . Military conflicts are another cause, and when they occur they are associated with increased rates of SCI. Another potential cause of SCI is iatrogenic injury, caused by an improperly done medical procedure such as an injection into the spinal column. SCI can also be of a nontraumatic origin. Nontraumatic lesions cause anywhere from 30 to 80% of all SCI;

13770-409: The cervical vertebrae other than the atlas, the anterior and posterior tubercles are on either side of the transverse foramen on each transverse process. The anterior tubercle on the sixth cervical vertebra is called the carotid tubercle because it separates the carotid artery from the vertebral artery . There is a hook-shaped uncinate process on the side edges of the top surface of the bodies of

13932-413: The cervical vertebrae. The thoracolumbar spine or thoracolumbar division refers to the thoracic and lumbar vertebrae together, and sometimes also their surrounding areas. The thoracic vertebrae attach to ribs and so have articular facets specific to them; these are the superior , transverse and inferior costal facets . As the vertebrae progress down the spine they increase in size to match up with

14094-411: The closure of the caudal neuropore and formation of the brain's ventricles that contain the choroid plexus tissue, the central canal of the caudal spinal cord is filled with cerebrospinal fluid. Earlier findings by Viktor Hamburger and Rita Levi-Montalcini in the chick embryo have been confirmed by more recent studies which have demonstrated that the elimination of neuronal cells by programmed cell death

14256-414: The coccyx. There are seven cervical vertebrae (but eight cervical spinal nerves ), designated C1 through C7. These bones are, in general, small and delicate. Their spinous processes are short (with the exception of C2 and C7, which have palpable spinous processes). C1 is also called the atlas , and C2 is also called the axis . The structure of these vertebrae is the reason why the neck and head have

14418-469: The convex articular feature of an anterior vertebra acts as the ball to the socket of a caudal vertebra. This type of connection permits a wide range of motion in most directions, while still protecting the underlying nerve cord. The central point of rotation is located at the midline of each centrum, and therefore flexion of the muscle surrounding the vertebral column does not lead to an opening between vertebrae. In many species, though not in mammals,

14580-412: The cortex. Additionally, some ALS axons from the spinomesencephalic pathway project to the periaqueductal gray in the pons, and the axons forming the periaqueductal gray then project to the nucleus raphes magnus , which projects back down to where the pain signal is coming from and inhibits it. This helps control the sensation of pain to some degree. Proprioceptive information in the body travels up

14742-420: The costal processes of thoracic vertebrae to form the ribs. Functions of vertebrae include: There are a number of congenital vertebral anomalies , mostly involving variations in the shape or number of vertebrae, and many of which are unproblematic. Others though can cause compression of the spinal cord. Wedge-shaped vertebrae, called hemivertebrae can cause an angle to form in the spine which can result in

14904-401: The damage of crashes, such as head restraints, air bags, seat belts, and child safety seats. Falls can be prevented by making changes to the environment, such as nonslip materials and grab bars in bathtubs and showers, railings for stairs, child and safety gates for windows. Gun-related injuries can be prevented with conflict resolution training, gun safety education campaigns, and changes to

15066-430: The disc. They also act as a semi-permeable interface for the exchange of water and solutes. The vertebral arch is formed by pedicles and laminae. Two pedicles extend from the sides of the vertebral body to join the body to the arch. The pedicles are short thick processes that extend, one from each side, posteriorly, from the junctions of the posteriolateral surfaces of the centrum, on its upper surface. From each pedicle

15228-428: The enveloping pia mater laterally between the dorsal and ventral roots. The dural sac ends at the vertebral level of the second sacral vertebra. In cross-section, the peripheral region of the cord contains neuronal white matter tracts containing sensory and motor axons . Internal to this peripheral region is the grey matter , which contains the nerve cell bodies arranged in the three grey columns that give

15390-432: The greatest detail. Thus it is the standard for anyone who has neurological deficits found in SCI or is thought to have an unstable spinal column injury. Neurological evaluations to help determine the degree of impairment are performed initially and repeatedly in the early stages of treatment; this determines the rate of improvement or deterioration and informs treatment and prognosis. The ASIA Impairment Scale outlined above

15552-554: The head); hyperextension (backward movement); lateral stress (sideways movement); rotation (twisting of the head); compression (force along the axis of the spine downward from the head or upward from the pelvis); or distraction (pulling apart of the vertebrae). Traumatic SCI can result in contusion , compression , or stretch injury. It is a major risk of many types of vertebral fracture . Pre-existing asymptomatic congenital anomalies can cause major neurological deficits, such as hemiparesis , to result from otherwise minor trauma. In

15714-423: The horns of the spinal cord. The white matter is located outside of the grey matter and consists almost totally of myelinated motor and sensory axons. Columns of white matter known as funiculi carry information either up or down the spinal cord. The spinal cord proper terminates in a region called the conus medullaris , while the pia mater continues as an extension called the filum terminale , which anchors

15876-401: The injury (same side), the body loses motor function, proprioception , and senses of vibration and touch. On the contralateral (opposite side) of the injury, there is a loss of pain and temperature sensations. If the injury is above pyramidal decussation there is contralateral hemiplegia, at the level of decussation there is completed motor loss on both sides and below pyramidal decussation there

16038-534: The injury is high enough in the neck to impair the muscles involved in breathing, the person may not be able to breathe without the help of an endotracheal tube and mechanical ventilator. The effects of injuries at or above the lumbar or sacral regions of the spinal cord (lower back and pelvis) include decreased control of the legs and hips , genitourinary system , and anus. People injured below level L2 may still have use of their hip flexor and knee extensor muscles. Bowel and bladder function are regulated by

16200-443: The injury site. In the long term, the loss of muscle function can have additional effects from disuse, including muscle atrophy . Immobility also can lead to pressure sores , particularly in bony areas, requiring precautions such as extra cushioning and turning in bed every two hours (in the acute setting) to relieve pressure. In the long term, people in wheelchairs must shift periodically to relieve pressure. Another complication

16362-417: The ipsilateral side as the ventral corticospinal tract. These axons also synapse with lower motor neurons in the ventral horns. Most of them will cross to the contralateral side of the cord (via the anterior white commissure ) right before synapsing. The midbrain nuclei include four motor tracts that send upper motor neuronal axons down the spinal cord to lower motor neurons. These are the rubrospinal tract ,

16524-541: The larger animals since they attach to the muscles and ligaments of the body. In the elephant , the vertebrae are connected by tight joints, which limit the backbone's flexibility. Spinous processes are exaggerated in some animals, such as the extinct Dimetrodon and Spinosaurus , where they form a sailback or finback. Vertebrae with saddle-shaped articular surfaces on their bodies, called "heterocoelous", allow vertebrae to flex both vertically and horizontally while preventing twisting motions. Such vertebrae are found in

16686-399: The leading cause of death in people with SCI, followed by infections, usually of pressure sores, urinary tract infections , and respiratory infections . Pneumonia can be accompanied by shortness of breath , fever, and anxiety . Another potentially deadly threat to respiration is deep venous thrombosis (DVT), in which blood forms a clot in immobile limbs; the clot can break off and form

16848-425: The length of the spine , the vertebrae change to accommodate different needs related to stress and mobility. Each vertebra is an irregular bone. A typical vertebra has a body ( vertebral body ), which consists of a large anterior middle portion called the centrum ( vertebral centrum , plural centra ) and a posterior vertebral arch , also called a neural arch . The body is composed of cancellous bone , which

17010-420: The length of the neck. This includes seemingly unlikely animals such as the giraffe, the camel, and the blue whale, for example. Birds usually have more cervical vertebrae with most having a highly flexible neck consisting of 13–25 vertebrae. In all mammals, the thoracic vertebrae are connected to ribs and their bodies differ from the other regional vertebrae due to the presence of facets. Each vertebra has

17172-418: The length of the spinal cord. Spinal cord injuries can be caused by trauma to the spinal column (stretching, bruising, applying pressure, severing, laceration, etc.). The vertebral bones or intervertebral disks can shatter, causing the spinal cord to be punctured by a sharp fragment of bone . Usually, victims of spinal cord injuries will suffer loss of feeling in certain parts of their body. In milder cases,

17334-539: The level of injury, the less extensive its effects. Injuries from T9 to T12 result in partial loss of trunk and abdominal muscle control. Thoracic spinal injuries result in paraplegia , but function of the hands, arms, and neck are not affected. One condition that occurs typically in lesions above the T6 level is autonomic dysreflexia (AD), in which the blood pressure increases to dangerous levels, high enough to cause potentially deadly stroke . It results from an overreaction of

17496-796: The level of the injury. Injury can occur at any level of the spinal cord and can be complete , with a total loss of sensation and muscle function at lower sacral segments, or incomplete , meaning some nervous signals are able to travel past the injured area of the cord up to the Sacral S4-5 spinal cord segments. Depending on the location and severity of damage, the symptoms vary, from numbness to paralysis , including bowel or bladder incontinence . Long term outcomes also range widely, from full recovery to permanent tetraplegia (also called quadriplegia) or paraplegia . Complications can include muscle atrophy , loss of voluntary motor control, spasticity , pressure sores , infections , and breathing problems . In

17658-468: The location and extent of the injury, from bed rest to surgery. In many cases, spinal cord injuries require long-term physical and occupational therapy , especially if it interferes with activities of daily living . In the United States , about 12,000 people annually survive a spinal cord injury. The most commonly affected group are young adult males. SCI has seen great improvements in its care since

17820-487: The lower limbs, loss of sensation, bowel and bladder dysfunction, and loss of reflexes. There may be bilateral sciatica with central disc prolapse and altered gait. Unlike conus medullaris syndrome, symptoms often occur only on one side of the body. The cause is often compression, e.g. by a ruptured intervertebral disk or tumor. Since the nerves damaged in CES are actually peripheral nerves because they have already branched off from

17982-477: The lumbar vertebrae (L5), but may also occur in the other lumbar vertebrae, as well as in the thoracic vertebrae. Spinal disc herniation , more commonly called a slipped disc , is the result of a tear in the outer ring ( anulus fibrosus ) of the intervertebral disc , which lets some of the soft gel-like material, the nucleus pulposus , bulge out in a hernia . This may be treated by a minimally-invasive endoscopic procedure called Tessys method . A laminectomy

18144-424: The lumen of the neural tube narrows to form the small central canal of the spinal cord. The alar plate and the basal plate are separated by the sulcus limitans. Additionally, the floor plate also secretes netrins . The netrins act as chemoattractants to decussation of pain and temperature sensory neurons in the alar plate across the anterior white commissure, where they then ascend towards the thalamus . Following

18306-434: The majority of cases the damage results from physical trauma such as car accidents , gunshot wounds , falls , or sports injuries , but it can also result from nontraumatic causes such as infection , insufficient blood flow , and tumors . Just over half of injuries affect the cervical spine , while 15% occur in each of the thoracic spine , border between the thoracic and lumbar spine , and lumbar spine alone. Diagnosis

18468-428: The medial part of the column. If the axon enters above level T6, then it travels in the cuneate fasciculus , which is lateral to the fasciculus gracilis. Either way, the primary axon ascends to the lower medulla , where it leaves its fasciculus and synapses with a secondary neuron in one of the dorsal column nuclei : either the nucleus gracilis or the nucleus cuneatus , depending on the pathway it took. At this point,

18630-472: The middle of the 20th century. Research into potential treatments includes stem cell implantation, hypothermia, engineered materials for tissue support, epidural spinal stimulation , and wearable robotic exoskeletons . Spinal cord injury can be traumatic or nontraumatic, and can be classified into three types based on cause: mechanical forces, toxic, and ischemic from lack of blood flow. The damage can also be divided into primary and secondary injury :

18792-430: The middle of the neck and no other painful injuries that could distract from neck pain. If these are all absent, no spinal motion restriction is necessary. If an unstable spinal column injury is moved, damage may occur to the spinal cord. Between 3 and 25% of SCIs occur not at the time of the initial trauma but later during treatment or transport. While some of this is due to the nature of the injury itself, particularly in

18954-526: The motor signal toward the target muscle. The descending tracts are composed of white matter. There are several descending tracts serving different functions. The corticospinal tracts (lateral and anterior) are responsible for coordinated limb movements. The corticospinal tract serves as the motor pathway for upper motor neuronal signals coming from the cerebral cortex and from primitive brainstem motor nuclei. Cortical upper motor neurons originate from Brodmann areas 1, 2, 3, 4, and 6 and then descend in

19116-423: The necks of birds and some turtles. "Procoelous" vertebrae feature a spherical protrusion extending from the caudal end of the centrum of one vertebra that fits into a concave socket on the cranial end of the centrum of an adjacent vertebra. These vertebrae are most often found in reptiles , but are found in some amphibians such as frogs. The vertebrae fit together in a ball-and-socket articulation, in which

19278-465: The neural tube begins to develop, the notochord begins to secrete a factor known as Sonic hedgehog (SHH). As a result, the floor plate then also begins to secrete SHH, and this will induce the basal plate to develop motor neurons . During the maturation of the neural tube, its lateral walls thicken and form a longitudinal groove called the sulcus limitans . This extends the length of the spinal cord into dorsal and ventral portions as well. Meanwhile,

19440-442: The overlying ectoderm secretes bone morphogenetic protein (BMP). This induces the roof plate to begin to secrete BMP, which will induce the alar plate to develop sensory neurons . Opposing gradients of such morphogens as BMP and SHH form different domains of dividing cells along the dorsal ventral axis. Dorsal root ganglion neurons differentiate from neural crest progenitors. As the dorsal and ventral column cells proliferate,

19602-530: The percentage varies by locale, influenced by efforts to prevent trauma. Developed countries have higher percentages of SCI due to degenerative conditions and tumors than developing countries. In developed countries, the most common cause of nontraumatic SCI is degenerative diseases, followed by tumors; in many developing countries the leading cause is infection such as HIV and tuberculosis. SCI may occur in intervertebral disc disease, and spinal cord vascular disease. Spontaneous bleeding can occur within or outside of

19764-665: The posterior limb of the internal capsule and end in the primary sensory cortex . The proprioception of the lower limbs differs from the upper limbs and upper trunk. There is a four-neuron pathway for lower limb proprioception. This pathway initially follows the dorsal spino-cerebellar pathway. It is arranged as follows: proprioceptive receptors of lower limb → peripheral process → dorsal root ganglion → central process →  Clarke's column  → 2nd order neuron → spinocerebellar tract →cerebellum. The anterolateral system (ALS) works somewhat differently. Its primary neurons axons enter

19926-422: The posterior limb of the internal capsule , through the crus cerebri , down through the pons, and to the medullary pyramids , where about 90% of the axons cross to the contralateral side at the decussation of the pyramids. They then descend as the lateral corticospinal tract. These axons synapse with lower motor neurons in the ventral horns of all levels of the spinal cord. The remaining 10% of axons descend on

20088-549: The primary sensory cortex via the posterior limb of the internal capsule. Some of the "pain fibers" in the ALS deviate from their pathway towards the VPLN. In one such deviation, axons travel towards the reticular formation in the midbrain. The reticular formation then projects to a number of places including the hippocampus (to create memories about the pain), the centromedian nucleus (to cause diffuse, non-specific pain) and various parts of

20250-419: The protective membranes that line the cord, and intervertebral disks can herniate. Damage can result from dysfunction of the blood vessels, as in arteriovenous malformation , or when a blood clot becomes lodged in a blood vessel and cuts off blood supply to the cord. When systemic blood pressure drops, blood flow to the spinal cord may be reduced, potentially causing a loss of sensation and voluntary movement in

20412-412: The range of movement possible. These facets are joined by a thin portion of the vertebral arch called the pars interarticularis . Vertebrae take their names from the regions of the vertebral column that they occupy. There are usually thirty-three vertebrae in the human vertebral column — seven cervical vertebrae , twelve thoracic vertebrae , five lumbar vertebrae , five fused sacral vertebrae forming

20574-443: The range of movement. Structurally, vertebrae are essentially alike across the vertebrate species, with the greatest difference seen between an aquatic animal and other vertebrate animals. As such, vertebrates take their name from the vertebrae that compose the vertebral column. In the human vertebral column , the size of the vertebrae varies according to placement in the vertebral column, spinal loading, posture and pathology. Along

20736-399: The region its butterfly-shape. This central region surrounds the central canal , which is an extension of the fourth ventricle and contains cerebrospinal fluid. The spinal cord is elliptical in cross section, being compressed dorsolaterally. Two prominent grooves, or sulci, run along its length. The posterior median sulcus is the groove in the dorsal side, and the anterior median fissure

20898-416: The relative locations of the spinal tracts responsible for each type of function. Brown-Séquard syndrome occurs when the spinal cord is injured on one side much more than the other. It is rare for the spinal cord to be truly hemisected (severed on one side), but partial lesions due to penetrating wounds (such as gunshot or knife wounds) or fractured vertebrae or tumors are common. On the ipsilateral side of

21060-433: The rest of the population. The risk of suicide is worst in the first five years after injury. In young people with SCI, suicide is the leading cause of death. Depression is associated with an increased risk of other complications such as UTI and pressure ulcers that occur more when self-care is neglected. Spinal cord injuries are most often caused by physical trauma . Forces involved can be hyperflexion (forward movement of

21222-399: The right and left posterior spinal arteries . These travel in the subarachnoid space and send branches into the spinal cord. They form anastomoses (connections) via the anterior and posterior segmental medullary arteries , which enter the spinal cord at various points along its length. The actual blood flow caudally through these arteries, derived from the posterior cerebral circulation,

21384-452: The risk of contractures ( shortening of muscles , tendons, or ligaments that result from lack of use of a limb); this problem can be prevented by moving the limb through its full range of motion multiple times a day. Another problem lack of mobility can cause is loss of bone density and changes in bone structure. Loss of bone density ( bone demineralization ), thought to be due to lack of input from weakened or paralysed muscles, can increase

21546-501: The risk of fractures. Conversely, a poorly understood phenomenon is the overgrowth of bone tissue in soft tissue areas, called heterotopic ossification . It occurs below the level of injury, possibly as a result of inflammation, and happens to a clinically significant extent in 27% of people. People with spinal cord injury are at especially high risk for respiratory and cardiovascular problems, so hospital staff must be watchful to avoid them. Respiratory problems (especially pneumonia) are

21708-472: The secondary axon leaves its nucleus and passes anteriorly and medially. The collection of secondary axons that do this are known as internal arcuate fibers . The internal arcuate fibers decussate and continue ascending as the contralateral medial lemniscus . Secondary axons from the medial lemniscus finally terminate in the ventral posterolateral nucleus (VPLN) of the thalamus , where they synapse with tertiary neurons. From there, tertiary neurons ascend via

21870-403: The separate vertebrae are usually called the caudal vertebrae . Because of the different types of locomotion and support needed between the aquatic and other vertebrates, the vertebrae between them show the most variation, though basic features are shared. The spinous processes which are backward extending are directed upward in animals without an erect stance. These processes can be very large in

22032-458: The skin, muscles, and visceral organs to be relayed to the brain. The roots terminate in dorsal root ganglia , which are composed of the cell bodies of the corresponding neurons. Ventral roots consist of efferent fibers that arise from motor neurons whose cell bodies are found in the ventral (or anterior) gray horns of the spinal cord. The spinal cord (and brain) are protected by three layers of tissue or membranes called meninges , that surround

22194-415: The smallest, lightest vertebrae and the vertebral foramina are triangular in shape. The spinous processes are short and often bifurcated (the spinous process of C7 is not bifurcated, and is substantially longer than that of the other cervical spinous processes). The atlas differs from the other vertebrae in that it has no body and no spinous process. It has instead a ring-like form, having an anterior and

22356-427: The somite, the sclerotome cells migrate medially toward the notochord . These cells meet the sclerotome cells from the other side of the paraxial mesoderm . The lower half of one sclerotome fuses with the upper half of the adjacent one to form each vertebral body. From this vertebral body, sclerotome cells move dorsally and surround the developing spinal cord , forming the vertebral arch . Other cells move distally to

22518-436: The spinal column and have spinal motion restricted to prevent damage to the spinal cord. Injuries or fractures in the head, neck, or pelvis as well as penetrating trauma near the spine and falls from heights are assumed to be associated with an unstable spinal column until it is ruled out in the hospital. High-speed vehicle crashes, sports injuries involving the head or neck, and diving injuries are other mechanisms that indicate

22680-492: The spinal cord and exit between a pair of vertebrae , to innervate a specific part of the body. The area of skin innervated by a specific spinal nerve is called a dermatome , and the group of muscles innervated by a single spinal nerve is called a myotome . The part of the spinal cord that was damaged corresponds to the spinal nerves at that level and below. Injuries can be cervical 1–8 (C1–C8), thoracic 1–12 (T1–T12), lumbar 1–5 (L1–L5), or sacral (S1–S5). A person's level of injury

22842-427: The spinal cord and then ascend one to two levels before synapsing in the substantia gelatinosa . The tract that ascends before synapsing is known as Lissauer's tract . After synapsing, secondary axons decussate and ascend in the anterior lateral portion of the spinal cord as the spinothalamic tract . This tract ascends all the way to the VPLN, where it synapses on tertiary neurons. Tertiary neuronal axons then travel to

23004-543: The spinal cord by a tumor or intervertebral disc . Anterior spinal artery syndrome also known as anterior spinal cord syndrome , due to damage to the front portion of the spinal cord or reduction in the blood supply from the anterior spinal artery , can be caused by fractures or dislocations of vertebrae or herniated disks. Below the level of injury, motor function, pain sensation, and temperature sensation are lost, while sense of touch and proprioception (sense of position in space) remain intact. These differences are due to

23166-427: The spinal cord is a continuation of the brainstem and anatomically begins at the occipital bone , passing out of the foramen magnum and then enters the spinal canal at the beginning of the cervical vertebrae . The spinal cord extends down to between the first and second lumbar vertebrae , where it tapers to become the cauda equina . The enclosing bony vertebral column protects the relatively shorter spinal cord. It

23328-403: The spinal cord or displacement of ligaments or disks that do not have accompanying spinal column damage. Thus when X-ray findings are normal but SCI is still suspected due to pain or SCI symptoms, CT or MRI scans are used. CT gives greater detail than X-rays, but exposes the patient to more radiation , and it still does not give images of the spinal cord or ligaments; MRI shows body structures in

23490-409: The spinal cord to the coccyx . The cauda equina ("horse's tail") is a collection of nerves inferior to the conus medullaris that continue to travel through the vertebral column to the coccyx. The cauda equina forms because the spinal cord stops growing in length at about age four, even though the vertebral column continues to lengthen until adulthood. This results in sacral spinal nerves originating in

23652-455: The spinal cord via three tracts . Below L2, the proprioceptive information travels up the spinal cord in the ventral spinocerebellar tract . Also known as the anterior spinocerebellar tract, sensory receptors take in the information and travel into the spinal cord. The cell bodies of these primary neurons are located in the dorsal root ganglia . In the spinal cord, the axons synapse and the secondary neuronal axons decussates and then travel up to

23814-399: The spinal cord, the injury has better prognosis for recovery of function: the peripheral nervous system has a greater capacity for healing than the central nervous system . Signs (observed by a clinician) and symptoms (experienced by a patient) vary depending on where the spine is injured and the extent of the injury. A section of skin innervated through a specific part of the spine

23976-467: The spinal cord, while the corticospinal fibers destined for the legs are spared due to their more external location. The most common of the incomplete SCI syndromes, central cord syndrome usually results from neck hyperextension in older people with spinal stenosis . In younger people, it most commonly results from neck flexion. The most common causes are falls and vehicle accidents; however other possible causes include spinal stenosis and impingement on

24138-495: The spinal cord. Spinal nerves, with the exception of C1 and C2, form inside the intervertebral foramen . These rootlets form the demarcation between the central and peripheral nervous systems. Generally, the spinal cord segments do not correspond to bony vertebra levels. As the spinal cord terminates at the L1–L2 level, other segments of the spinal cord would be positioned superior to their corresponding bony vertebral body. For example,

24300-406: The spinal cord. The dorsal column–medial lemniscus pathway (DCML pathway), and the anterolateral system (ALS). In the dorsal column-medial lemniscus pathway, a primary neuron's axon enters the spinal cord and then enters the dorsal column. Here the dorsal column connects to the axon of the nerve cell. If the primary axon enters below spinal level T6, the axon travels in the gracile fasciculus ,

24462-403: The spinal curvature diseases of kyphosis , scoliosis and lordosis . Severe cases can cause spinal cord compression. Block vertebrae where some vertebrae have become fused can cause problems. Spina bifida can result from the incomplete formation of the vertebral arch. Spondylolysis is a defect in the pars interarticularis of the vertebral arch. In most cases this occurs in the lowest of

24624-460: The spine if they are still inside a vehicle or other confined space. The use of a cervical collar has been shown to increase mortality in people with penetrating trauma and is thus not routinely recommended in this group. Modern trauma care includes a step called clearing the cervical spine , ruling out spinal cord injury if the patient is fully conscious and not under the influence of drugs or alcohol, displays no neurological deficits, has no pain in

24786-617: The system to a stimulus such as pain below the level of injury, because inhibitory signals from the brain cannot pass the lesion to dampen the excitatory sympathetic nervous system response. Signs and symptoms of AD include anxiety, headache , nausea , ringing in the ears , blurred vision, flushed skin, and nasal congestion . It can occur shortly after the injury or not until years later. Other autonomic functions may also be disrupted. For example, problems with body temperature regulation mostly occur in injuries at T8 and above. Another serious complication that can result from lesions above T6

24948-415: The technology of guns, including trigger locks to improve their safety. Sports injuries can be prevented with changes to sports rules and equipment to increase safety, and education campaigns to reduce risky practices such as diving into water of unknown depth or head-first tackling in association football. A person's presentation in context of trauma or non-traumatic background determines suspicion for

25110-420: The third to the seventh cervical vertebrae and of the first thoracic vertebra. Together with the vertebral disc, this uncinate process prevents a vertebra from sliding backward off the vertebra below it and limits lateral flexion (side-bending). Luschka's joints involve the vertebral uncinate processes. The spinous process on C7 is distinctively long and gives the name vertebra prominens to this vertebra. Also

25272-420: The thoracic vertebral body articulates with the head of the rib . The transverse process of a lumbar vertebra is also sometimes called the costal or costiform process because it corresponds to a rudimentary rib ( costa ) which, as opposed to the thorax, is not developed in the lumbar region. There are superior and inferior articular facet joints on each side of the vertebra, which serve to restrict

25434-441: The upper lumbar region. For that reason, the spinal cord occupies only two-thirds of the vertebral canal. The inferior part of the vertebral canal is filled with cerebrospinal fluid and the space is called the lumbar cistern. Within the central nervous system (CNS), nerve cell bodies are generally organized into functional clusters, called nuclei , their axons are grouped into tracts . There are 31 spinal cord nerve segments in

25596-426: The vertebra body give attachment to the intervertebral discs . The posterior part of a vertebra forms a vertebral arch , in eleven parts, consisting of two pedicles ( pedicle of vertebral arch ), two laminae, and seven processes . The laminae give attachment to the ligamenta flava (ligaments of the spine). There are vertebral notches formed from the shape of the pedicles, which form the intervertebral foramina when

25758-440: The vertebrae articulate . These foramina are the entry and exit conduits for the spinal nerves . The body of the vertebra and the vertebral arch form the vertebral foramen, the larger, central opening that accommodates the spinal canal , which encloses and protects the spinal cord . Vertebrae articulate with each other to give strength and flexibility to the spinal column, and the shape at their back and front aspects determines

25920-419: The vertebral body, project laterally from either side at the point where the lamina joins the pedicle , between the superior and inferior articular processes. They also serve for the attachment of muscles and ligaments, in particular the intertransverse ligaments . There is a facet on each of the transverse processes of thoracic vertebrae which articulates with the tubercle of the rib . A facet on each side of

26082-409: The vertebral column, the nerves of the lower spinal segments form a bundle called the cauda equina. There are two regions where the spinal cord enlarges: The spinal cord is supplied with blood by three arteries that run along its length starting in the brain, and many arteries that approach it through the sides of the spinal column. The three longitudinal arteries are the anterior spinal artery , and

26244-441: Was in common use. Central cord syndrome , almost always resulting from damage to the cervical spinal cord, is characterized by weakness in the arms with relative sparing of the legs, and spared sensation in regions served by the sacral segments. There is loss of sensation of pain, temperature, light touch, and pressure below the level of injury. The spinal tracts that serve the arms are more affected due to their central location in

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