WHAT CAUSES BACK PAIN?

 

Back problems are extremely common and costs governments, employers and the people suffering with the injury enormous amounts of money. Because the specific cause of the problem is often difficult to diagnose, and the symptoms either intermittent or vague, or recurring on and off, some people think they are not a serious injury. To ignore a back injury is a mistake, once an injury has been done it can become chronic, and many people end up either living with pain, or taking pain medications long term. Treatment often does not completely rectify the problem, partially because, while nursing their back injury, people will tend to rely on other muscles, and use/strain them in tasks they were not designed for. To untrain these unconscious behaviours is very difficult and requires a lot of conscious attention to every day behaviours that most people perform without thinking. By far, the best course of action with back injuries is to prevent them in the first place, and failing that, seek intensive treatment quickly.

TERMINOLOGY

There is extensive terminology to be familiar with when it comes to back injuries. The basic terms include:

Movement/Location Terms

- Anterior: In front of

- Posterior: Behind

- Superior: Above

- Inferior: Below

- Extension : Increasing the angle between two bones

- Flexion: Decreasing the angle between two bones

- Elevation: Upward movement

- Depression: Downward movement

- Abduction: Movement of a bone away from the middle of the body

- Adduction: Movement of a bone toward the middle of the body

- Rotation: Circular movement (such as turning your head)

- Compression: Increasing the overall pressure on a structure

- Torsion: External forces that twist a structure

- Hyper: Over, above, higher than normal, too great, excessive

- Hypo: Under, lower, less than normal, deficient

Spinal Column

Approximately 45cm (18 inch) long in most individuals, the spine is the anatomical structure that surrounds the spinal cord. It consists of bones called vertebrae and fluid filled connective tissue discs.

Spinal Cord

The major bundle of nerves that run from the brain through the intervertebral foramen of the vertebrae that make up the spine.

Vertebrae

The small bones that make up the spinal column and through which the nerve bundles from the brain run. There are 23 vertebrae in the spinal column. The main section of a vertebra is known as the ‘body’. The nerve bundles run through a hole on the posterior side of the body known as the intervertebral foramen. The foramen is encompassed by the vertebral arch from which extend seven spiny processes. (Singular = vertebra)

Inter-vertebral Discs

Connective tissue that binds two verterbrae together, with a fluid/gel centre (nucleus) to provide cushioning and dampening of external forces surrounded by an outer fibrous layer (annulus).

Inter-vertebral Foramen

The space in the posterior portion of each vertebra through which nerve bundles run.

Facet Joint

Also known as zygapophysial joints, they are located on the back of the spine and function to lock together adjoining vertebrae in the lumbar spine. This limits forward sliding of vertebrae over each other, as well as restricting rotation, to protect against spinal torsion injuries. The synovial fluid in the joint acts like a lubricant to allow other spinal movements to proceed smoothly. As with all joints, these can be affected by arthritic diseases which degrade the cartilage and inhibit synovial fluid production.

Cervical Spine

The uppermost section of the spine, comprised of 7 cervical vertebrae. They are generally smaller and more delicate than the vertebrae beneath them. C1 (atlas) and C2 (axis) are the neck vertebrae.

Thoracic Spine

The longest region of the spine that runs between the cervical and lumbar regions. Consists of 12 vertebrae, the spinal processes of which articulate with the ribs.

Lumbar Spine

The region of the spine that bears the most weight, and is comprised of the thickest most robust vertebrae. Located between the thoracic and pelvic spinal regions it has 5 vertebrae.

Sacral (Pelvic) Spine

The base of the spine, made up of 5 vertebrae that are fused in adulthood. (No interverterbral discs)

Sciatic Nerve

The largest nerve in the body, which originates in the lumbar/sacral spine (L4-S3). It supplies both sensory and motor innervation to the legs.

Idiopathic

A disease or illness whose cause is not determinable.

The term “back problem” is itself quite vague and generic. More specifically a person with a sore back may be suffering a:

- Spinal injury (vertebrae or discs are injured or have shifted out of normal alignment)

- Muscular injury (sprains, strains, tears, hernias)

- Nerve Injury (nerves are pinched, stuck, irritated, partially or completely severed)

SPINAL INJURIES

There are a range of spinal injuries. They may affect the small bones of the spinal column known as vertebrae, the ligaments that join and stabilise them or the cushioning connective tissue discs that separate them. The cause may be a direct force (impact by blunt objects), an indirect force (car accident, fall etc) repeated incorrect lifting or exercising, excessive exercise, particularly in children and adolescents, or by degeneration and aging. The symptoms can be quite diverse. Some of the more common spinal injuries are listed below.

Fracture

A break in the bone (in this case vertebrae). In vertebrae it may be a hairline crack, or the complete snapping off of one of the spinous processes.

Dislocation

The displacement of an anatomical structure (generally a bone) from its normal positions, similar to the term sublaxation.

Subluxation

A term used almost exclusively by modern chiropractors to refer to a misalignment of the vertebrae.

Stenosis

A degenerative condition where the interverterbral foramen is narrowed by abnormal new bony growths, shrinking the area for the nerves to exit the spinal canal.

Bulging Disc

Early stage of herniation where a portion of the disc begins to bulge out from between the vertebrae. Also known as a prolapsed or slipped disc.

Herniated Disc

A portion gel-like inner nucleus of the disc has ruptured or torn the outer fibrous disc coating (the annulus) and has pushed through it into the spinal canal, limiting the space for the spinal cord. Also known as a ruptured disc. Differs from a bulging or prolapsed disc where the annulus is not ruptured.

Thinning/Degenerated Disc

The result of aging or chronic injury. The disc will become thinner and ragged and will gradually become less able to separate the vertebrae and absorb shocks.

Congenital

A condition present at birth.

Spinal Ligament Sprain

The partial or complete tearing of one of the ligaments of the spinal column.

Facet Joint Syndrome

Condition where the facet joints (known as the zygapophysial joints) found on the back of the spine cause pain. The specific cause can be arthritis, forced spinal extension (backward bending) or traumatic spinal rotation.

Cauda Equina Syndrome

Rare but extremely serious spinal condition at the very base of the spine. Distinguished from other painful lower back conditions because pain is present on both sides. Sufferers will also have symptoms related to bowel and bladder control and sexual function. Motor and sensory nerve signal transmission is affected. Emergency medical treatment is required, generally involving surgery.

Kyphosis

The normal thoracic curvature. When it is abnormally exaggerated curvature a person will have a ‘rounded’ back. In most cases it is due to poor posture, however it can also be congenital.

Lordosis

The normal lumbar curvature of the back. When it is abnormally exaggerated, a person will have an extreme inward curvation of the lower back. This is called sway back.

Spondylolisthesis

Condition where a vertebra slips over the vertebra beneath it. Can be congenital.

Spina Bifida

A neural tube defect that results in a malformed spine. Varies between individuals, but generally the vertebrae do not develop normally in utero and may have gaps. In more severe cases a vertebra, or several vertebrae may not form at all, leaving portions of the spinal cord without normal bony protection. Some babies will also be born with a cyst on the back where the lining tissue of the spinal cord (meninges) has protruded. This is called a meningocele. In the most severe cases, the spinal cord itself will also protrude into the cyst, forming a myelomeningocele (Spina bifida aperta). The degree of disability will depend on the degree of spinal malformation. Women planning to fall pregnant, or who are already pregnant are advised to take a folic acid supplement to avoid this condition in their unborn child.

Scoliosis

A condition where the spine curves to one side. Abnormal curvature can occur at any place along the length of the spine, and toward either side of the body. Most commonly, the mid (thoracic) to lower (lumbar) spine is affected and the condition develops during childhood. It can also, less commonly, be present at birth. The curvature may leave the hips uneven or cause one scapula to protrude, depending on the specific location and severity of the curvature. The cause is generally never determined, although there is a genetic component, and in many cases a relationship to another spinal deformity (such as spina bifida) or injury.

MUSCULAR INJURY

As for muscles in other areas of the body, abnormal pressure, tension or force can injure the muscles of the back. However, muscular back injuries can be very difficult to diagnose and treat. The individual muscles will often insert into a number of different bones, or to different places on the same bone. An injury in a single muscle may therefore cause pain over a wide area, with a wide range of movements, and may affect the ability not only to move the spine, but also to move the limbs. Treatment is problematic because many of the muscles are either necessary for posture, stability and necessary torso movements, making immobilisation almost impossible. Many are also very deep within the body, covered by one or more other large muscles, making physical manipulation (osteopathy, massage, physiotherapy) very difficult. The major muscles in the back region are the:

Trapezius

Runs from the base of the skull down to the thoracic spine and outwards to the scapulae (shoulder blades) and over the top of the torso to the clavicles (collarbones).
Functions in many of the clavicle and scapula movements, and head extension

Latissimus dorsi

Runs from the lower six thoracic vertebrae to the base of the spine and the pelvis and wraps around to the lower ribs. Overlapped slightly by the trapezius in the thoracic spine region.
Functions in most of the movements of the arms

Gluteal Muscles (maximus, medius and minimus)

The maximus gives the shape of the buttocks, the medius is located directly beneath the maximus, and the minimus directly beneath that. Maximus runs from the very base of the spine to the pelvis and femur (thigh bone). Medius and minimus run from the pelvis to the femur.
Work together to control some movements of the thigh

Obliques

Wrap around the sides of the body. The external obliques run from the lower ribs to the pelvis. The internal obliques are beneath the external obliques, and run from the pelvis to the lower ribs.
Allow abdominal movements and lateral vertebral movements

Deeper, beneath these large muscles are the spinal muscles that specifically allow spinal movements. They are long, thin muscles that run up and down the spine, connecting to ribs, vertebrae, the pelvis and the skull. They are quite numerous, but can be categorised as:

Splenius Muscles

Splenius capitus and cervicus. Movements of the head.

Erector Spinae

Largest muscular mass of the back, comprising the iliocostalis (run outside the other Erector spinae muscles – towards the sides of the body), longissimus (between iliocostalis and spinalis) and spinalis (middle of the back, close to spine) muscles. All run longitudinally, parallel to each other.
Allow spinal extension and maintain posture

Transversospinalis Muscles

Semispinalis thoracis, cervicus and capitis, as well as Multifidus and Rotatores muscles.
Extension and rotation of the spinal column

Segmental Muscles

Interspinales and Intertransversarii muscles.
Extension and lateral flexion (bending over to the side) of the spinal column

Scalene Muscles

Anterior, middle and posterior scalene muscles.
Neck flexion and rotation.

Muscles and bones are connected by bands of extremely strong fibrous tissue:

Ligament

Fibrous tissue connection between bones (or cartilages). Provide support and stability over joints and assist in permitting joint movements.

Tendon

Fibrous tissue connection between a muscle and bone.

Injuries to the muscles and tendons include:

Sprain

An injury to a ligament. Can be a small tear to a complete separation from the bone.

Strain

An injury to a muscle. Tearing of the muscle tissue will generally result in bleeding and a hematoma.

Tear/Laceration

Generic term, used to describe an injury where muscle fibres, or adjoining a natomical structures are forcibly separated from each other.

Hernia

Where an organ/muscle/tissue protrudes through an abnormal opening in a lining or muscle wall. In terms of a muscle injury, it can be either that the muscle is the protruding tissue, or the muscle could be damaged by the protrusion of another structure through it.

Atrophy

To waste away. Can refer to a cell, an organ or a tissue. Muscles that are unused for extended periods will atrophy, resulting in weakness.

A common back injury today is whiplash, more correctly known as a neck hyperextension injury. This is the consequence of sudden, forceful jerking of the head forward and backward, often with an equally sudden and forceful stop. The cervical vertebrae are the smallest and most fragile, as well as being the least well supported by surrounding musculature. The injury is partially due to the strain on the muscles caused by the extreme range of the movement, as well as the strain on the muscles we instinctively tense up trying to brace our necks and stop the movement.

NEUROLOGICAL INJURIES

There are two main functions of the nerves – sensory (detecting pain, touch, heat, cold etc) and motor (movement, both voluntary and involuntary). Nerve damage in the context of back injury is generally a secondary complication of spinal injuries, that is, they tend to occur because of a spinal injury. Vertebrae or disc that have been damaged/injured can compress (squash), impinge on (encroach on the space for a nerve, or pinch it), irritate (physically rub against) or partially or completely sever (cut in half) a nerve. The subsequent symptoms will vary depending on the function of the damaged/destroyed nerve and the degree of injury. The nerves exiting the spinal column are single long cells. Some examples of the symptoms a person may experience from a serious back injury with disc/vertebrae movement or damage and subsequent nerve injury include:

Sensation Changes

Numbness, tingling (pins and needles) or burning in the limbs and extremities the nerve runs to.

Pain

Can be dull or sharp, mild or very severe localised or radiating out into the limbs the nerve serves. Can also be chronic, or in response to certain movements

Abdominal Pain

Caused by irritation of nerves serving the abdominal organs

Digestive Complications

Can occur if the motor nerves that serve the stomach are injured

Severe Headaches

Can also be due to muscle strains, or a combination of both muscle injury and irritation of nerves exiting through the cervical vertebrae.

Paralysis, Partially or Complete Loss of Normal Function

Occurs if nerves are partially or completely severed, or if nerves are pinched. Affected nerves are those that send motor signals, rather than sensory signals. Weakness may also occur in affected limbs.

Some specific nerve injuries of the back and spinal cord include:

Pinched Nerve

Also known as impingement, this is a condition where a nerve is compressed between two adjacent structures. In the back, pinched nerves are generally the result of bulging or herniated discs. The symptoms depend on which nerve root is affected, but generally involves considerable pain.

Trapped Nerve

Also known as a stuck nerve. A condition where a nerve becomes stuck to surround soft tissues, such as muscle or connective tissue. Repeated injuries cause the formation of scar tissue and may also damage the protective sheath around the nerve, leading to the formation of adhesions and nerves become trapped. This can occur within the back, close to the spine, or at other locations in the periphery (away from the spinal cord) where nerves travel through soft tissues.

Sciatica

A condition where a lower back injury causing pinching of the sciatic nerve. The result is often excruciating pain radiating from the lower back, through the buttocks and into the leg. Commonly the result of herniated discs in the lower spine.

 

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