spine diagrams and educational videos

SPINAL ANATOMY

The spine is a very complex mechanical structure that is highly flexible yet very strong and stable. In the normal spine, regardless of your position or activity, including sleeping, there is always some type of physical demand being placed on it.

The primary functions of the spine include:

• Protect the spinal cord, nerve roots, and internal organs
• Provide flexibility of motion
• Provide structural support and balance for upright posture. The spine bears the load of the head, shoulders and arms, and upper body. The upper body weight is then distributed to the hips and legs. The spine attempts to keep the body's weight balanced evenly over the pelvis. This reduces the amount of work required by the spinal muscles and can eliminate muscle fatigue and back pain.

Lumbar Spine Anatomy	Cervical Spine Anatomy	Intervertebral Disc

The normal adult spine is balanced over the pelvis, requiring minimal workload on the muscles to maintain and upright posture.

Loss of spinal balance can result in strain to the spinal muscles and deformity of the spine as it attempts to maintain an upright posture.

Regions of the Spine
There are 33 vertebrae (bones) in the spine. Anatomically, the spine is divided into four regions:

• The top 7 vertebrae that form the neck are called the cervical spine and are labeled C1-C7.
• The upper back, or thoracic spine, has 12 vertebrae, labeled T1-T12.
• The lower back, or lumbar spine has 5 vertebrae, labeled L1-L5.
• The sacrum and coccyx (tailbone) are made up of 9 vertebrae that are fused together to form a solid bone. The sacrum is labeled S1.

Curves of the Spine
When viewed from the front or back, the normal spine is in a straight line, with each vertebra sitting directly on top of the other. A side-to-side curve in the spine is called a scoliosis.

When viewed from the side, the normal spine has three gradual curves:

• The neck has a lordosis; it curves toward the back.
• The thoracic spine has a kyphosis; it curves toward the front.
• The lumbar spine also has a lordosis.

These curves help the spine to support the load of the head and upper body, and maintain balance in the upright position.

Vertebrae
Although the vertebrae have slightly different appearances as they range from the cervical spine to the lumbar spine, they all have the same basic structures, and the structures have the same names. Only the first and second cervical vertebrae are structurally different in order to support the skull.

Each vertebra has an anterior arch and a posterior arch, which form a hole, called a foramen. The spinal cord passes through foramen of each vertebra.

The anterior arch is called the vertebral body. Discs connect one vertebral body to another to allow motion of the spine and cushion it against heavy loads. Together, the vertebral bodies and discs bear about 80 percent of the load to the spine.

The posterior arch consists of the pedicles, laminae, and processes.

The pedicles are two short cylinders of bone that extend from the vertebral body. Nerve roots branch off the spinal cord and exit to the body between the pedicles of two vertebrae. If the spine becomes unstable, the pedicles may compress the nerve root, cause pain or numbness.

Laminae are two flattened plates of bone that form the walls of the posterior arch. Over time, the laminae may thicken, a process called stenosis. This thickening compresses the spinal cord and/or nerves causing pain or numbness.

The articular, transverse, and spinous processes project off the laminae. Ligaments and tendons attach to the processes. The articular processes join one vertebra to another posteriorly.

The transverse processes extend out on either side of the laminae. The spinous process is the bony projection that can be felt through the back of someone's skin.

Intervertebral Discs
Intervertebral discs are located between each vertebra from C2-C3 to L5-S1. Combined, they make up one fourth the height of the spinal column. The discs act as shock absorbers to the loads placed on the spine and allow movement of the spine. Movement at a single disc level is limited, but all of the vertebrae and discs combined allow for a significant range of motion.

The intervertebral disc is made up of two components: the annulus fibrosus and the nucleus pulposus. The annulus fibrosus is the outer portion of the disc. It is composed of layers of collagen and proteins, called lamellae. The fibers of the lamellae slant at 30-degree angles, and the fibers of each lamella run in a direction opposite the adjacent layers. This creates a structure that is exceptionally strong, yet extremely flexible.

The nucleus pulposus is the inner gel material surrounded by the annulus fibrosus. It makes up about 40 percent of the disc. This ball-like gel is contained within the lamellae. The nucleus is composed primarily of loose collagen fibers, water, and proteins. The water content of the nucleus is about 90 percent at birth and decreases to about 70 percent by the fifth decade.

Injury or aging of the annulus fibrosus may allow the nucleus pulposus to be squeezed through the annulus fibers either partially, causing the disc to bulge, or completely, allowing the disc material to escape the disc. The bulging disc or nucleus material may compress the nerves or spinal cord, causing pain.

In the early years of life, the discs have a blood supply that nourishes them. In the second and third decades, discs gradually lose this blood supply, until they are avascular. At this point, the disc begins to degenerate, or age. By the age of 50, over 95 percent of all people will have disc degeneration. The disc begins to lose water content and shrinks. The spine's range of motion and shock-absorbing ability are decreased. This may result in injury to the nerves and vertebrae, and the aging disc itself may generate pain.

Spinal Cord and Nerve Roots
The brain and spinal cord together make up the central nervous system. The spinal cord is located immediately below the brain stem. It extends through the foramen magnum, a hole at the base of the skull.

The spinal cord functions as a sophisticated network that carries information from the outer elements of the body (skin, muscles, ligaments, joints) through the sensory tracts, to the central "computer," the brain. Data are processed there, and new information such as muscle control is sent out through the motor tracts of the spinal cord.

The spinal cord ends as the conus medullaris at the L1 vertebral level, where it branches into the cauda equina, a collection of nerves that extend from the conus medularis to the sacrum. The conus medularis nerves float freely in spinal fluid, making it possible to pass a needle safely into the area to draw a sample of spinal fluid or inject drugs, anesthetics, or radiologic substances for x-ray, MRI or CT scan.

BACK PAIN

Low back pain can often be attributed to complex origins and symptoms, and it does not discriminate. It can originate from identified muscle trauma, or an unknown non-traumatic event. Low back pain can also begin in other regions of the body and eventually attack the muscles or other structures in the lower back. Sometimes low back pain can even begin in the nerves or nervous system. Other origins for low back pain are postneural difficulties, congenital disorders, trauma, infections, degenerative disorders, inflammatory diseases, circulatory disorders or any of other 30 additional causes.

Where Back Pain Starts

It is often difficult for physicians to pinpoint the exact cause of a patient's low back pain, because of the complex composition of the human spine. Bone, discs, muscles, ligaments, tendons and various other tissues are arranged like a three-dimensional puzzle to make up the spine. The complex make up can easily mask the exact cause of low back pain.

In addition, depression, anxiety, frustration, reinforcement, stress, anger, fear and many other psychological states can help to cause the onset of back pain, can be a reaction to prolonged pain, or exist concurrently with pain.

The emotional component can complicate the back pain diagnosis, sometimes resulting in needless surgery and disability and can sometimes mask the underlying physical causes of pain.

Mechanical Disorders

Lumbar Disc Herniation

As a result of the natural wear and tear that occurs with aging, certain parts of the spine start to degenerate and wear out, as we grow older. This process makes some of the anatomic structures of the spine, the bones, intervertebral discs, ligaments, and muscles less flexible and less resistant to injury.

Spondylolisthesis

Spondylolysis is a defect in the lamina of the vertebrae in the pars interarticularis, usually the fourth or the fifth lumbar vertebrae in the lower (lumbar) spine. Spondylolysis may occur as a congenital defect or be the result of repetitive trauma. Some physicians believe spondylolysis may be caused by genetics, and that someone could be born with thin vertebral bones causing them to be vulnerable to the condition. Spondylolysis is common in teenage gymnasts and football players, and presents with lower back pain that is worse with strenuous exercise or activity. Radiographic findings are subtle, but bone scans or CT scans will usually detect the lesion. Activity modification, bracing, or surgical treatment may be indicated for persistent symptoms.

Spondylolysis is a prerequisite for spondylolisthesis. Spondylolisthesis occurs when spondylolysis weakens one of the vertebrae so much that the bone slips out of place.

The condition can also be caused by degenerative disc disease. If the vertebrae slip too much and begin to press on nerves, surgery may become necessary. Spondylolisthesis may also be caused by degenerative conditions that affect the vertebral joints, such as cerebral palsy.

Early treatment usually involves rest and medication. Progressive spondylolisthesis usually requires surgical treatment.

Sprains and Strains
Most acute pain in the back results from sustaining a mild strain in the back or back musculature. Sprains and strains in your lower back usually happen during a sudden and stressful injury, causing stretching or tearing of the muscles, tendons, or ligaments in your lower back. When you strain or sprain your lower back it causes a lot of stress on your spine, irritating it. If you have this condition you may also suffer from painful muscle spasms which can occur during your daily activities or at night while you're sleeping. The pain is usually limited to five or ten days.

Sciatica
Sciatica is the descriptive term for when pain runs from your back or buttocks down your leg and into your foot
It is a condition caused by either compression or trauma of the sciatic nerve. Sciatica is made worse when you cough or if someone lifts your leg up while you are laying down. Symptoms may begin abruptly or gradually, are usually irritated by movement, and often grow worse at night. Sciatica implies that there is an irritation of your nerve root in the lower part of your spine. In some instances, this could be due to a ruptured or herniated disc in your lower back.

Herniated Disc

Herniated / Ruptured Discs
A herniated ("slipped") or ruptured disc in your back can cause each of these pain patterns. The ways in which a slipped disc causes different pain patterns and problems with your back is related to the location of the slipped disc along your spine, and also to the anatomy of your spinal column.
The spinal column, or backbone, consists of 33 bones (vertebrae) and can be divided into five segments, called the cervical, thoracic, lumbar, sacral, and coccygeal sections of the spine. Each of these sections corresponds to a particular part of your body. The cervical spine is that part of the spine in your neck, the thoracic spine supports your trunk, the lumbar spine supports your lower back and abdomen, the sacrum supports your pelvis, and the coccyx is your tailbone.

Spinal Stenosis

Stenosis
Stenosis produces a dull, aching pain in the lower back when standing or walking. The pain usually radiates down into the buttocks and thighs, and can be relieved by stopping to rest, or by using a walker or a shopping cart in the grocery store. These symptoms usually slowly get worse over time, and people who suffer from spinal stenosis will notice a slow decrease in their ability to walk shorter and shorter distances.

Lumbar stenosis is a natural product of aging, and the wear and tear on the spine throughout our lives. As our bodies grow older, the ligaments and bones that make up the spine grow thicker and become stiffer. The spinal canal gradually narrows, and the spinal cord is slowly compressed. The lack of space interferes with the normal function of the spinal cord and the body becomes less able to function normally.

Inflammatory and Infectious Disorders

Though infections and inflammation of the spine are rare, if they are neglected for a period of time, or if there is a delay in diagnosis, they can become a significant source of pain and disability. Bone and joint infections anywhere in the body can be crippling and life threatening.

Discitis
Discitis is a low-grade infection that affects the disc space between two vertebrae. Although discitis is uncommon, children under ten are usually the ones affected by this condition which is the result of an inflammation caused by staphylococcus, viruses, or other inflammatory processes. Discitis is characterized by the slow onset of severe back pain and may or may not be associated with fever, chills, sweats, feeling tired, loss of appetite or other symptoms. The diagnosis is usually made by seeing narrowing of the disc space between two vertebrae and a bone scan that shows that the disc and adjacent vertebrae are "hot" on the scan. This condition can be very painful and is often aggravated by any movement of the spine. The pain often travels to other parts of the body including the abdomen, hip, leg, or groin. It usually occurs in the lower (lumbar) back and upper (thoracic) back.

Spinal Infection
Young children with this condition are usually irritable and uncomfortable and refuse to sit up, stand or walk. The treatment of discitis generally involves antibiotics, rest, and a brace. Surgery is rarely needed.

Ankylosing Spondylitis
Ankylosing spondylitis is a rare condition that can cause back and neck pain. It is a rheumatic inflammatory disease that affects the spine and sacroiliac joints. Although it primarily attacks the spine (usually the low back first), this chronic and painful disease can also attack other joints, tendons and ligaments, and the chest wall.

Over time, this disease can cause the vertebral bodies in the spine to fuse together. When this happens, patients with ankylosing spondylitis can have difficulty moving freely. Common symptoms for ankylosing spondylitis are gradually occurring back pain and stiffness (usually over a period of weeks or months). Early morning stiffness is often helped with a warm shower or light exercise. Symptoms last longer than three months.

In particularly severe cases, patients may be unable to look above the level of the horizon, or they may develop a significant amount of pain from having a hunched over posture. Ankylosing spondylitis is usually diagnosed using x-rays of the sacroiliac joints, looking for changes in the tissues caused by inflammation. However, tissue changes are not always visible.

Tumors

Tumors of the spine and spinal cord are relatively uncommon. The most common initial symptom that patients with a spinal tumor have is pain. Because back pain is very common, it is also not a specific symptom of any one disease or medical condition. Spinal cord tumors can be either primary (originating in the spinal cord) or secondary (metastases of cancer that originated elsewhere in the body). Therefore, the challenge is to determine how to evaluate back pain with the goal of specifically excluding a tumor as the cause of the pain. Luckily, most back pain is not due to a tumor. However, if a cancer were discovered after a long period of "conservative" management of back pain, most patients would feel that their problem should have been investigated more thoroughly in the beginning.

Benign Tumors
Doctors use the term "benign" to indicate that a particular tumor is unlikely to spread to others parts of the body. Benign tumors can still be a significant problem however, depending upon their location, size, adjacent structures, blood supply, and other factors. Fortunately, most benign tumors can be treated successfully.

Malignant Lesions
Doctors use the term "malignant" to indicate that a particular tumor or a cancer often spreads to other parts of the body, and can be difficult to cure or treat. This is very different from "benign" cancers, which are much less likely to spread, are easier to treat and control.

Trauma

It is impossible to predict how badly someone's spine has been injured before a doctor has evaluated them. Therefore, everyone who is involved in an accident that could have damaged their back is treated as if they do have an injury to their spine. Most people are familiar with the "backboards" that paramedics use to transport accident victims, but they are unaware of how important these devices are in keeping the spine stable while they are taken to the hospital.

Paramedics and emergency response teams treat accident victims according to strict protocols that have been developed in order to save lives. These protocols are designed to minimize the possibility that someone with a spine injury could be injured while moving him or her from the accident scene or while taking them to a hospital. With these protocols, cervical collars are placed on all accident victims, they are secured on a back-board, and then taken to a hospital for further evaluation.

Spinal Cord Injuries
Each year in the United Sates, there will be approximately 50,000 new spinal cord injuries caused by accidents. A spinal cord injury occurs when the cord itself is crushed, stretched, or torn by the accident.

Unfortunately, this is still an injury that can not be reversed or cured by modern medicine. More than half of these injuries involves the cervical spine, and most of them happen to young men. These injuries are incredibly devastating to the patient, their families, and also to their communities. There is currently a lot of research being done on ways to minimize spine injuries by designing cars for better safety, improving protective gear like football helmets, and educating people about the dangers of certain activities.

There is also a lot of research being done on how to care for someone immediately after they have had a spinal cord injury, and also what kind of rehabilitation is best for them.

Osteoporosis

Osteoporosis is a disorder caused by a decrease in the amount of calcium in your bones, which can cause the bones in your spine to break because they are too weak to support the weight of the body. When this happens, people usually suffer from sharp back pain, and they often become shorter or have a "hunched over" posture. If you have these symptoms you could be suffering from osteoporosis.

Osteoporosis is a disease that affects more than eight million women and two million men. It is characterized by low bone mass and deterioration of bone tissue which can lead to fragile bones and increased risk in fractures of the spine, hip and wrist. More than 700,000 vertebral fractures every year are caused by osteoporosis.

Osteoporosis is some times called the "silent disease" because bone loss has no symptoms, and the disease usually remains painless until a bone breaks. Although the disease can affect any bone, spinal or vertebral compression fractures can have serious consequences including loss of height, severe back pain, and deformity, a curving of the shoulders and back, and a thickening waistline. Women in particular reach their maximum bone mass at about the age of 20. After that, they will gradually lose bone mass. In the 5-7 years immediately following menopause, women will lose up to 20% of their bone mass. When osteoporosis affects the spine, there is a gradual collapse of the vertebrae producing back pain, loss of overall height, and a stooped posture. The back pain at vertebral collapse may be severe at times.

Neck Pain

Neck pain and symptoms caused by a cervical (neck) spine disorder are a very common problem for many adult Americans. The cervical spine is composed of many different anatomic structures, including muscles, bones, ligaments, and joints. Each of these structures has nerve endings that can detect painful problems when they occur. The different parts of the cervical spine are normally well balanced and able to handle all of the movements, stresses, and strains of the body gracefully. However, when the different parts of the cervical spine are injured or start to wear out, your neck can be a significant source of pain and discomfort.

Studies show that approximately fifty percent of the population has evidence of degenerative changes in their cervical spine by the age of fifty. These changes happen because the discs that act as shock absorbers between the vertebral bodies of the cervical spine wear out, as we grow older. As the intervertebral disks wear out, they begin to collapse, or herniate, and become less flexible. The common causes of neck pain and cervical disorders include arthritis, injuries, and trauma. In some situations neck pain can also be a warning sign of something more serious such as spinal cord compression, a tumor, or spinal infection.

Any patient suffering from neck, shoulder, head or arm pain should be examined by a doctor in order to determine where the pain originates and what is causing the pain. The tissues involved in producing the pain must also be identified, and how they are being irritated must also be understood. The history of the pain and any activities that may have triggered it are also important factors in diagnosis and treatment. Impairment of movement in any part of the cervical spine can be responsible for pain, discomfort, and disability.

Mechanical Disorders

As a result of the natural wear and tear that occurs with aging, certain parts of the cervical spine start to degenerate and wear out, as we grow older. This process makes some of the anatomic structures of the cervical spine, the bones, intervertebral discs, ligaments, and muscles less flexible and less resistant to injury.

Degenerative Disc
Degenerative disc disease (DDD) is part of the natural process of growing older. Unfortunately, as we age, our intervertebral discs lose their flexibility, elasticity, and shock absorbing characteristics. The ligaments that surround the disc, called the annulus fibrosis, become brittle and they are more easily torn. At the same time, the soft gel-like center of the disc, called the nucleus pulposus, starts to dry out and shrink. Degenerative disc disease is as certain as death and taxes, and to a certain degree this process happens to everyone. However, not everyone who has degenerative changes in their cervical spine has pain. Many people who have "normal" necks have MRI's that show disc herniations, degenerative changes, and narrowed spinal canals. Every patient is different, and it is important to realize that not everyone develops symptoms as a result of degenerative disc disease.

Herniated Disc
There are soft-tissue discs between the bony vertebral bodies in your cervical spine that are called intervertebral discs. These discs are composed of a soft gel-like center called the nucleus pulposus, and a tough outer lining that surrounds the disc called the annulus fibrosis. The intervertebral disc creates a joint between each of the vertebral bodies that allows them to flex and extend, rotate slightly, and move with respect to one another. When the outer lining that surrounds the disc tears, the soft center squeezes out through the opening, creating a "herniated", "slipped", or "ruptured disc". Each of these terms describes the same process.

Myelopathy
Myelopathy is a term that means that there is something wrong with the spinal cord itself. This is usually a later stage of cervical spine disease, and is often first detected as difficulty walking due to generalized weakness or problems with balance and coordination. This type of process occurs most commonly in the elderly, who can have many reasons for having trouble walking or problems with gait and balance. However, one of the more worrisome reasons that these symptoms are occurring is that bone spurs and other degenerative changes in the cervical spine are squeezing the spinal cord. Myelopathy affects the entire spinal cord, and is very different from isolated points of pressure on the individual nerve roots.

Radiculopathy
Doctors use the term radiculopathy to specifically describe pain, and other symptoms like numbness, tingling, and weakness in your arms or legs that are caused by a problem with your nerve roots. The nerve roots are branches of the spinal cord that carry signals out the rest of the body at each level along the spine. This term comes from a combination of the Latin word radix, which means the roots of a tree, and the Latin word pathos, which means a disease. This disease is often caused by direct pressure from a herniated disc or degenerative changes in the cervical spine that cause irritation and inflammation of the nerve roots.

Spondylolysis
Cervical spondylolysis is a disorder that narrows the spinal canal in the neck compressing the spinal cord or spinal nerve roots. It's a fracture or defect in the pars anticulars (a portion of the bone between each of the joints of the back), allowing one vertebral body to slide forward on the next. Spondylolyosis is sometimes referred to as pars interarticularis defect. It may be unilateral or bilateral and is usually due to a developmental defect but may be secondary to a fracture. Spondylolysis affects the area of the vertebra called the pedicle. The pedicle is part of the bony ring that protects the spinal nerves, and is the portion that connects the vertebral body to the facet joints. It's a disease that often times affects middle-aged and older adults who have degenerative discs and vertebrae in their neck. When a spondylolysis is present, the back part of the vertebra and the facet joints simply are not connected to the body, except by soft tissue.

Stenosis
Stenosis is a term used to describe a narrowing of various parts of the body. Cervical stenosis is a degenerative disease where the spinal canal and neural foramina narrow and compress the spinal cord and nerve roots. Stenosis occurs when pressure increases inflaming the facet joints. The facet joints are overlapping arches that form the spinal canal. These joints are covered with cartilage and a membrane. Degenerative changes and wear and tear can cause the facet joints to inflame. This disorder is most common in people over 50 years of age. However, genetics and congenital factors may predispose a person for stenosis.

Inflammatory and Infectious Disorders

Though infections and inflammation of the cervical spine are rare, if they are neglected for a period of time, or if there is a delay in diagnosis, they can become a significant source of pain and disability. Bone and joint infections anywhere in the body can be crippling and life threatening, and infections in the cervical spine are no exception.

Ankylosing Spondylitis
Ankylosing spondylitis is a rare condition that can cause back and neck pain. It is a rheumatic inflammatory disease that affects the spine and sacroiliac joints. This disease is three times more likely to develop in men than in women and it usually occurs between the ages of 20 and 40. Although it primarily attacks the spine (usually the low back first), this chronic and painful disease can also attack other joints, tendons and ligaments, and the chest wall. Though its cause is unknown, ankylosing spondylitis tends to run in families which suggests that genetics plays a role in the development of this disease. A patient is 10 to 20 times more likely to have ankylosing spondylitis if a parent or sibling also has this condition.

Juvenile Rheumatoid Arthritis
Juvenile Rheumatoid Arthritis is a type of inflammatory arthritis that affects almost 200,000 children in the United States. JRA is a disease that causes painful, swollen, and stiff joints in children, most commonly in large joints like the knee. JRA has three well-defined subsets: a monoarticular form, which means that that the disease affects only one joint; a polyarticular form, which means that it affects many joints, and a systemic form, which means that it affects other organs in the body besides the joints. The systemic form of the disease is most often associated with high fevers and rash, in addition to arthritis. The polyarticular and systemic forms of the disease are the two types that commonly affect the cervical spine.

Rheumatoid Arthritis
Rheumatoid Arthritis is among the most debilitating forms of arthritis causing joints to ache, throb and even deform over time. The exact cause of this inflammatory condition is not known, but it is believed to be caused by an attack on the synovium (tissue that lines the joints) by the body's immune system. The upper cervical spine can be damaged by the inflammation that is caused by rheumatoid arthritis. This disease is three times more common in women than in men and usually occurs between the ages of 20 and 50. Just like the gradual destruction of other joints in the body, several joints between the base of the skull and uppermost vertebral bodies in the cervical spine are very susceptible to damage from rheumatoid arthritis.

Tumors

Tumors of the spine and spinal cord are relatively uncommon. The most common initial symptom that patients with a spinal tumor have is pain. Because neck pain, and pain caused by a cervical (neck) disorder is very common, it is also not a specific symptom of any one disease or medical condition. Spinal cord tumors can be either primary (originating in the spinal cord) or secondary (metastases of cancer that originated elsewhere in the body). Therefore, the challenge is to determine how to evaluate neck pain with the goal of specifically excluding a tumor as the cause of the pain. Luckily, most neck pain is not due to a tumor. However, if a cancer were discovered after a long period of "conservative" management of neck pain, most patients would feel that their problem should have been investigated more thoroughly in the beginning.

Benign Tumors
Doctors use the term "benign" to indicate that a particular tumor is unlikely to spread to others parts of the body. Benign tumors can still be a significant problem however, depending upon their location, size, adjacent structures, blood supply, and other factors. Fortunately, most benign tumors can be treated successfully.

Malignant Lesions
Doctors use the term "malignant" to indicate that a particular tumor or a cancer often spreads to other parts of the body, and can be difficult to cure or treat. This is very different from "benign" cancers, which are much less likely to spread, are easier to treat and control.

Trauma

Cervical spine injuries can occur during motor vehicle accidents, in rough contact sports, after a fall, or by hitting your head against a hard surface, such as when diving into a pool that is too shallow. These accidents can cause injuries that range from mild cases of neck pain, called whiplash, to injuries that can cause paralysis of the rest of the body below the level of injury.

Whiplash
Whiplash is the common term used for a hyperextension injury to the neck. Though the neck is a very flexible structure, it can be injured when the weight of the head exceeds the neck's ability to control its motion. The injury usually happens when the head is suddenly jerked back and forth beyond its normal limits during a car accident, rough contact sports, or a fall. This jerking motion can cause over-stretching and tearing of the neck muscles and ligaments and can cause the discs between the neck vertebrae to bulge, tear or rupture.

Disc Herniations
The discs that act as shock absorbers between the vertebral bodies of the cervical spine can be damaged during an accident. When this happens, the material in the center of the disk can be pushed out from where it normally is, a process called disk herniation. A herniated disk can put pressure on the spinal cord or nerves to the arms and legs. In situations when a disk ruptures very quickly, as in the case of an accident, then the nerve does not have any time to adjust to the increased pressure and it may stop working.

Fractures and Dislocations
Fractures and dislocations of the cervical spine demand early and accurate diagnosis so that treatment can quickly be introduced in order to produce a painless, stable neck and prevent pressure on the spinal cord and/or nerves. When the neck is injured in very violent accidents, the bones in the neck can be broken or pulled forcefully out of normal alignment. Fractures and dislocations of the cervical spine are very serious injuries because there is the potential for damage to the spinal cord if the patient is not taken care of very carefully.

Spinal Cord Injuries
Each year in the United Sates, there will be approximately 50,000 new spinal cord injuries caused by accidents. A spinal cord injury occurs when the cord itself is crushed, stretched, or torn by the accident. Unfortunately, this is still an injury that can not be reversed or cured by modern medicine. More than half of these injuries involves the cervical spine, and most of them happen to young men. These injuries are incredibly devastating to the patient, their families, and also to their communities. There is currently a lot of research being done on ways to minimize spine injuries by designing cars for better safety, improving protective gear like football helmets, and educating people about the dangers of certain activities. There is also a lot of research being done on how to care for someone immediately after they have had a spinal cord injury, and also what kind of rehabilitation is best for them.

BRAIN DIAGRAMS AND EDUCATIONAL VIDEOS

CRANIAL ANATOMY

The Skull

The skull is made up of 22 bones: the cranium includes eight bones that surround and protect the brain and 14 bones that form the face. In adults, all but one of the skull bones are fused together by immovable joints called sutures. The sutures lock the edges of the skull bones together, like pieces in a puzzle, to form a structure that is both rigid and strong. The mandible, or lower jaw, the only moveable skull bone, allows the mouth to open and close.

In newborns, the skull bones are not completely fused; they are linked by fibrous membrane called fontanels. Fontanels allow the skull to be compressed slightly during birth and accommodate growth of the brain during early infancy. By one-and-a-half years of age, the skull sutures have formed and the fontanels have disappeared.

Cranial Bones
The frontal bone forms the forehead. Two parietal bones form the sides of the cranial roof. Two temporal bones form the lower cranial sides. The occipital bone forms the cranial rear and floor. The ethmoid bone forms part of the nasal cavity. Shaped like a butterfly, the sphenoid bone forms the middle part of the cranial floor.

Facial Bones
The 14 facial bones provide the structure of the face and form the openings through which food, water, and air enter the body. Each of the following facial bones are paired: the maxillae form the upper jaw and front of the hard palate; the zygomatic bones form the cheeks; the nasal bones form the bridge of the nose; the lacrimal bones form part of the orbit, or eye socket; the palatine bones form the rear of the hard palate; and the inferior nasal conchae divide the nasal cavity. The vomer is a single bone that makes up part of the nasal septum, which divides the nostrils, and the mandible forms the lower jaw. The maxillae and mandible secure the teeth.

Small holes in the skull bones, called foraminae, and canals enable blood vessels, such as the carotid arteries and nerves, to enter and leave the skull. The spinal cord passes through a largest hole, called the foramen magnum, in the base of the cranium to join the brain. The occipital condyles on either side of the foramen magnum articulate with the first vertebra (C1) of the spine to permit up-and-down movement of the head.

The Nervous System

The nervous system is a communication network that controls and coordinates most body actions. People are not generally conscious of some of these activities as they occur, such as regulating body temperature, breathing, or heart rate. Others, we consciously control, such as movement, talking, eating, and thinking.

The nervous system has two main parts: the central and the peripheral nervous system. The brain and spinal cord make up the central nervous system, or CNS. The nerves branching off the central nervous system make up the peripheral nervous system, or PNS. The PNS consists of nerves bundles made up of sensory and motor neurons.

Neurons
The nervous system is made up of cells called neurons. Neurons are long, thin cells that transmit electrical impulses. Neurons have many branched endings, called dendrites, which receive impulses from other neurons. An axon, or nerve fiber, carries nerve impulses to other neurons or to muscle. Neurons do not touch, but are separated by a tiny gap called a synapse. When an impulse arrives at the end of an axon, it releases chemicals that generate an impulse in the dendrites of the neighboring neuron.

There are three types of neurons: sensory, motor, and association. Sensory neurons transmit nerve impulses from sense organs (eyes, ears, nose, tongue, and touch) to the brain. They also carry nerve impulses to the brain and spinal cord. Motor neurons transmit nerve impulses from the brain and spinal cord to a specific area of the body. A nerve impulse to a muscle, for example, may cause it to contract. Association neurons make up 90 percent of all neurons and are found only in the brain and spinal cord.

Nerves
Nerves consist of bundles of both sensory and motor neurons.

Brain
The brain is the control center of the nervous system. It enables us to think, feel, and move. The brain constantly receives information and sends out instructions to the body through the spinal cord and the body's vast network of nerves.

There are 12 pairs of cranial nerves branching off the brain. These nerves relay impulses from the sensory organs, such as the eyes or ears. Thirty-one pairs of spinal nerves branch off the spinal cord, exiting between each level of vertebrae. These nerves relay impulses to and from the rest of the body.

The largest part of the brain is the cerebrum, which controls the most sophisticated functions, such as thought, imagination, memory, emotion, speech, and sensory perception. The human cerebrum is quite large. It has two halves, or hemispheres. A band of nerve tissue, called the corpus callosum, links two halves to allow them to exchange information. Each hemisphere is covered by a layer of gray tissue, called the cerebral cortex, which is responsible for the higher functions of the brain, including conscious thought. The cortex is composed of sulci (folds) and gyri (bulges), which together provide a large surface area in the limited space inside the skull.

The cortex of each hemisphere has four lobes: the occipital, temporal, parietal, and frontal lobes. The occipital lobe controls vision. The temporal lobe controls sound and speech. The parietal lobe controls movement, touch, and recognition. And the frontal lobe controls thinking and planning.

The brain stem and hypothalamus control automatic processes, such as breathing and heartbeat.

The cerebellum acts as a "mini brain" that coordinates body balance, posture, and movement.

Brain tissue is soft and delicate, and requires protection. In addition to the protection provided by the skull, the brain is surrounded by: the connective tissue membranes, or meninges; the dura mater; the arachnoid layer; and the pia mater. Beneath the arachnoid matter is a wide space filled with cerebrospinal fluid (CSF). This fluid forms a liquid cushion that reduces the weight of the brain and protects it from knocks and jolts. CSF also helps the brain to receive nourishment.

Brain Tumors

A tumor is an abnormal mass of tissue that grows on or inside the body. It is known as primary if located where its growth first started, or secondary if it began growing elsewhere in the body and metastasized, or spread, to its present location. Most primary brain tumors do not metastasize outside the brain.

Brain Tumor

Inside the skull, tumors can grow almost anywhere: within brain tissue, from the meninges, or inside the ventricular system. They can be encapsulated (self-contained) or interwoven with blood vessels, nerves, or other brain structures from which they cannot be removed without devastating consequences. Metastatic tumors are usually well localized, may occur alone or in clusters, and may spread throughout much of the brain.

A benign tumor usually is encapsulated, does not spread to other areas of the body, grows slowly, and often causes problems by compressing brain tissue. A malignant tumor grows uncontrollably, spreads throughout the brain, and destroys brain tissue.

What symptoms can it cause?
A brain tumor may at first cause the vague feeling of being "unwell." This may be followed by other, more specific symptoms: dull, persistent headache; nausea or vomiting; generalized weakness; vision problems. Because the left side of the brain governs the right side of the body, and vice versa, a tumor will cause specific weakness or loss of movement on the opposite side of the body. Some symptoms may be caused by the increased pressure inside the skull from brain swelling, which can temporarily be treated with a steroid medication.

Because brain tissue is irritated by the tumor, the brain can temporarily "short-circuit" as its normal electrical activity is interrupted. These periods of uncontrolled brain activity can cause seizures, which may be generalized and cause contractions of all parts of the body, loss of consciousness or bladder and bowel function. The seizures may instead be of a focal nature, affecting only one arm, a leg, or part of the face. Seizures usually can be controlled with anticonvulsant medications.

How is it evaluated?
A detailed history-taking of the patient's symptoms and a physical examination are done first, followed by any of several tests, such as x-ray studies, Computerized Tomography (CT) scans, Magnetic Resonance Imaging (MRI), and angiograms. All findings are used to evaluate the patient's symptoms, determine the tumor's exact location, and provide the physician with a tentative diagnosis of the tumor type.

During surgery, ultrasound imaging may be used to pinpoint the tumor's precise location and help the surgeon plan his approach for its removal.

If an emergency craniotomy is required, an extensive workup may not be possible.

Meningioma

Growing from abnormal cells of the meninges, meningioma is a slow-growing tumor that shares the dura's rich blood supply. It is very often attached to dura and so may be immediately visible when the dura is opened.

It is usually a benign tumor and well encapsulated, but removal may be complicated by its size, firmness, and attachment to vital blood vessels or brain tissues.

A large meningioma or one that is difficult to remove may require a long, tedious surgery and can cause further brain swelling and blood loss.

Often the dura removed during tumor surgery may be replaced with other body tissue (fascia) or a dura substitute.

Glioma

Glial cells support the brain's functioning nerve network and are the site of tumors inside the brain. Gliomas are "graded" according to their degree of malignancy.

Often when the dura is opened, the brain is swollen but otherwise may appear normal.

The "center" of the glioma may readily be identified, but because the tumor gradually spreads into surrounding tissue the boundaries of a glioma are harder to identify.

It may take months for the cells around the edges of the tumor to appear abnormal, yet they can be affected long before they "show" themselves. This is why glioma usually cannot be removed completely, as even one remaining cell can continue the tumor's growth.

Metastatic Tumor

Often lying close to the brain's surface, where it irritates the normal tissue around it, a metastatic tumor is one that began in another body organ and traveled in the bloodstream to the brain.

Grown from a "seed" of non-brain tissue (from the breast, kidney, or lung, for example) a metastatic tumor often can be separated from the surrounding brain more easily. It only a single lesion exists, all or part of it usually can be surgically removed.

vascular diagrams and educational videos

CRANIAL ANATOMY

Subarachnoid Hemorrhage

Hemorrhage is the medical term for bleeding. The rupture of one of the brain's blood vessels can cause bleeding into the subarachnoid space - beneath the arachnoid membrane, on top of the pia mater - and into brain tissue. The bleeding usually stops, at least temporarily, when a clot forms over the ruptured area.

Why does it happen?
The most frequent cause of spontaneous subarachnoid hemorrhage (not due to injury) is the rupture of a small aneurysm, or bulging sac, on one of the blood vessels that supplies the brain. It is usually impossible to determine why the aneurysm forms and bursts, but the condition is common in adults and may be associated with aging, diabetes, pregnancy, hypertension (high blood pressure), heredity, or trauma.

Cerebral aneurysms are usually of three types: saccular with a narrow "neck" (called "berry" aneurysms because of their shape and their tendency to occur in clusters); saccular with a broad base; and fusiform, in which a short section of the artery bulges all the way around. Each shape determines the degree of difficulty a surgeon faces in attempting to treat the problem.

An aneurysm ruptures spontaneously - even during sleep - and therefore is not related to the strain of hard work, sexual intercourse, or other physical activity.

Although it is not always possible to discover the exact source of bleeding, other causes of spontaneous subarachnoid hemorrhage include: arteriovenous malformations, small angiomas, certain types of infections, and bleeding disorders.

Subarachnoid Hemorrhage

What symptoms can it cause?
A ruptured cerebral aneurysm at first causes severe headache, which can be followed by nausea, vomiting, double vision or sensitivity to light, neck pain or stiffness, weakness, memory loss, paralysis, coma, or death.
How severe the symptoms are and how long they last will depend on the amount and location of the bleeding. Blood in and around the brain can cause pressure, swelling, and brain irritation, which can lead to drowsiness, confusion, weakness or paralysis, memory loss, speech problems, behavior changes, or coma (complete loss of consciousness).

What complications can occur?
The blood vessels around the aneurysm are irritated by the blood from the hemorrhage and will at times go into a state of spasm, tightening and narrowing. This vasospasm ("vaso" meaning vessel) can occur any time after the rupture until the hemorrhaged blood has been absorbed by the body, and it can increase any or all symptoms. It is the body's own attempt to prevent a second hemorrhage by restricting the flow of blood through the vessels around the aneurysm. Vasospasm thus reduces pressure on the delicate aneurysm but unfortunately also reduces the normal blood supply to parts of the brain.

Ongoing research is being done to discover a medicine that will control vasospasm; as yet, none has proven effective.
Other complications from subarachnoid hemorrhage, such as hydrocephalus, hematoma (blood clot), and brain swelling, involve the brain; but other body systems can also be affected because of the severe nature of the illness. Pulmonary embolus, heart abnormalities, and bleeding from an ulcer may cause further complications.

How is it diagnosed?
Several tests are used to confirm the diagnosis of ruptured cerebral aneurysm. Some are explained in the latter portion of this section.

Because cerebrospinal fluid flows within the subarachnoid space, a sample of CSF taken during a spinal tap at the base of the spine will show blood from the hemorrhage. A CT scan will show blood inside the skull and indicate how much bleeding has occurred.

To find the source of the hemorrhage, an angiogram is performed, which may have to be repeated to try to pinpoint the aneurysm's exact location.

Hospitalization

Activity
Because the aneurysm can rupture again, a quiet, restful atmosphere is important. The patient usually is placed in the Intensive Care Unit (ICU), a highly specialized area providing close observation with specialized nursing care. Complete bedrest without physical strain is essential while the patient's condition stabilizes - usually in preparation for surgery.

Medications
Medications will be given when necessary to reduce pain, control blood pressure, relieve stress, and maintain fluid balance.

Breathing
If necessary, a respirator may be used to help the patient breathe and to control intracranial pressure. Most often, however, oxygen is merely administered to the patient through nasal prongs or a mask.

Monitoring devices
Various monitoring devices may be used to assess the patient's condition during recuperation. Among the most common are: an EKG (heart) monitor, an ICP monitoring device, a Swan-Ganz catheter to assess the patient's fluid balance, and an arterial line to continuously measure blood pressure and aid in drawing frequent blood samples for laboratory study.

Nutrition
Intravenous (I.V.) fluids may be given until liquids and food can be taken adequately by mouth. The amount of fluid given will be closely monitored until the dangers of brain swelling (edema) and vasospasm lessen.