Spine

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Spine

• Prof. Saeed Abuel Makarem

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Spinal fractures

• Spinal fractures are different than a broken arm
  or leg.
• A fracture or dislocation of a vertebra can cause
  bone fragments that pinch or damage the spinal
  nerves or even the spinal cord.
• Most spinal fractures occur due to
• Car accidents,
• Falls,
• Gunshot, or
• Sports.
• Injuries can range from mild ligament or muscle
  strains, to fractures and dislocations of the
  vertebrae, and debilitating spinal cord damage.

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Spinal fractures

• Depending on how severe your injury is, you may
  experience
• Pain,
• Difficulty walking,
• Unable to move your arms or legs (paralysis).
• Many fractures heal with conservative treatment.
• However severe fractures may require surgery.
• To understand spinal fractures, it is helpful to
  understand how your spine are formed and works.

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SPINAL COLUMN

• The vertebral column is a complex construct that
  includes a variety of
• Bones,
• Joints,
• Tendons,
• Nerves,
• Ligaments,
• Muscles and
• Vessels
• All woven together.
• The spines extends from the base of the skull to
  the pelvis.
• Ligaments, joints, muscles and tendons connect
  the bones together and keep them aligned.

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SPINAL COLUMN

• It is consists of 24 single vertebrae and 2
  bones,
• Sacrum and
• Coccyx, which made from fused vertebrae.
• Of the 24 single bones,
• 7 vertebrae in the neck (cervical),
• 12 vertebrae in the chest (thoracic), and
• 5 supporting the lower back and are called
  (lumbar).

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• Body or Centrum
• Anterior discoid, weight-bearing part of the
  vertebra.
• And
• Vertebral arch
• 2 pedicles and
• 2 Laminae.
• They join together to complete the arch.
• Vertebral foramen Between body and the arch and
  contains the spinal cord, ligament, fat and
  blood vessels.
• The arch carries 7 processes.
• 2 Transverse processes two lateral projections
  from the vertebral arch.

TYPICAL VERTEBRA

• One spinous process single posterior projection
  arising from the vertebral arch.
• 2 Superior and 2 inferior articular processes
  paired projections allowing a vertebra to
  articulate with adjacent vertebrae.

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C E R V I C A L VERTEBRA
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The vertebrae in each region have unique features
that help them to perform their main functions.
ATLAS AXIS

• The 7 cervical vertebrae (identified as C1 to
  C7).
• The first two (atlas axis) are different
  because they perform functions not shared by the
  other cervical vertebrae.
• The neck has the greatest range of motion
  because of these 2 specialized vertebrae.

The atlas has no body. The superior surfaces of
its 2 lateral masses contain large kidney- shaped
facet that articulate with the occipital
condyles. This joint allows you to nod- that is
to say "yes." Atlanto-occipital joint. The axis
acts as a pivot for the rotation of the atlas
(and the skull above). It has a large upright
process, called the odontoid process, or dens,
which acts as the pivot joint. The atlantoaxial
joint allows you to rotate your head that is to
say "no."
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TYPICAL CERVICAL VERTEBRAE

• The "typical" cervical vertebrae (C3 to C7) are
  the smallest, lightest vertebrae.
• Their spinous processes are often short and
  bifid, except the 7th.
• Its transverse processes contain foramina through
  which the vertebral vessels pass.
• The main function of the cervical spine is to
  support the weight of the head (about 10 pounds).
• Also, it is the most movable region of the spine.

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THORACIC VERTEBRAE

• The 12 thoracic vertebrae (T1 toT12) are larger
  than the cervical vertebrae.
• The body is somewhat heart-shaped and has two
  costal demifacets on each side, which receive the
  heads of the ribs.
• The spinous process is long and hooks sharply
  downward.
• The range of motion in the thoracic spine is
  limited.

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LUMBAR VERTEBRAE

• The 5 lumbar vertebrae (L1-- L5) have massive,
  block like bodies.
• They have short, hatchet-shaped spinous
  processes.
• They are the most solid of all vertebrae.
• Their main function is to bear the weight of the
  body.
• They also have a moderate range of movements.

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SACRUM

• The sacrum is formed of 5 fused vertebrae.
• It articulates with L5 above.
• And below with the coccyx.
• It also articulate with the hip bones at the
  alae, to form the sacroiliac joints.
• The sacrum forms the posterior wall of the
  pelvis.
• Its dorsal midline surface is roughened by the
  median sacral crest, (fused dorsal spines).
• The median sacral crest is flanked laterally by
  the dorsal sacral foramina.
• The sacral canal is the continuation of the
  vertebral canal.

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COCCYX

• The coccyx is formed of 3 to 5 (usually 4) tiny,
  irregularly shaped vertebrae.
• Also called the tailbone it provides attachment
  for ligaments and muscles of the pelvic floor.

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Intervertebral Discs

• The vertebral bodies are separated by pads of
  flexible fibrocartilage called intervertebral
  discs.
• The discs looks like a jelly doughnut
• There are a total of 23 discs in the spinal
  column.
• There are no discs between the Atlas Axis and
  Sacrum Coccyx.
• The intervertebral discs forms about one fourth
  of the whole length of the spinal column.
• Its primary function
• It act as a shock absorber between 2 adjacent
  vertebrae.
• It also acts as a cartilaginous joints that allow
  for slight mobility.
• It also acts as ligaments that hold the vertebrae
  together.
• Intervertebral discs are avascular and receive
  its nutrition from the vertebral end plates.

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Intervertebral Discs

• The intervertebral discs are formed of an outer
  annulus fibrosus and an inner soft, jelly-like
  material (nucleus pulposus).
• The annulus fibrosus is a strong radial tirelike
  structure made up of concentric lamellae of
  collagen fibers connected to the vertebral end
  plates.
• The nucleus pulposus contains a mucoprotein
  gellike material that is sealed by the annulus
  fibrosus.
• The nucleus pulposus needs to be well-hydrated in
  order to maintain its strength and softness.
• It serve as the major carrier of the bodys axial
  load that resists compression.

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Intervertebral Discs

• Both the annulus fibrosus and nucleus pulposus
  are composed of
• Water,
• Collagen, and
• Proteoglycans (PGs).
• The amount of fluid (water PGs) is greatest in
  the nucleus pulposus.
• PG molecules are important as they can attract
  and retain water in the discs.
• The amount of water in the nucleus varies
  throughout the day depending on the body
  activity.
• Unfortunately, the amount of water becomes less
  by old age.

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Intervertebral Discs

• The vertebral discs in the spine is an
  interesting and unique structure.
• The nucleus acts like a ball-bearing when you
  move, allowing the vertebral bodies to roll over
  the incompressible gel.
• The gel-filled nucleus is composed mostly of
  fluid.
• This fluid absorbed during the night as you lie
  down and is pushed out during the day as you move
  upright.

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HERNIATED DISC

• With age, our discs increasingly lose the ability
  to reabsorb fluid and become brittle and flatter.
• This is why we get shorter as we grow older.
• Also diseases, such as osteoarthritis
  osteoporosis, can cause bone spurs (osteophytes)
  to grow.
• Injury and strain can cause the nucleus to
  herniate, out of the annulus and compresses the
  nerve roots causing back pain.

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HERNIATED DISC

• The herniated disc is usually prevented to
  herniate posteriorly because of the presence of
  the posterior longitudinal ligament,(PLL).
• Herniation is mostly posterolateral.
• So disk herniation impinge on a spinal nerves
  rather than on the spinal cord itself!

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Curvatures

• The S-shaped curves of the vertebral column work
  together with the discs to prevent shock to the
  head when we walk or run.
• They also make the body trunk flexible.
• Curves act like a coiled spring to absorb shock,
  maintain balance, and allow range of motion
  throughout the spinal column.
• The spinal curves in the thoracic and sacral
  regions are referred to as primary curves as they
  are present when we are born.
• Later, the secondary curves develop.
• The cervical curve appears by the 6th month, when
  the baby begins to set and hold his head.
• While the lumbar curve develops by the end of the
  1st year, when the baby begins to walk.

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Muscles and Posture

• Muscles and correct posture maintain the natural
  spinal curves.
• Good posture involves training your body
• To stand up,
• To walk,
• To sit,
• To lie down, and
• To carry weight.
• So that the least amount of strain are placed on
  the spine during movement or weight-bearing
  activities.
• Excess body weight, big abdominal belly, weak
  muscles, and other factors can affect the spinal
  alignment.

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Spine

• It is important to know that
• Strong Bones
• Strong Muscles,
• Flexible Tendons,
• Flexible Ligaments
• Sensitive Nerves.
• All Contribute to a healthy spine.
• Keeping your spine healthy is vital if you want
  to live an active life without back pain.

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Abnormal Spinal Curves

• An icreased curvature of the thoracic spine is
  called kyphosis, or hunch back.
• An abnormal curve of the lumbar spine is called
  lordosis, or sway back.
• An abnormal curve from side-to-side is called
  scoliosis.

Kyphosis
Lordosis
Scoliosis
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Muscles

• Flexor are in the front and include the abdominal
  muscles.
• These muscles enable us to flex, or bend forward,
  and are important in lifting and controlling the
  arch in the lower back.

• Two main muscle groups that affect the spine are
  extensors and flexors.
• Extensor muscles enable us to stand up lift
  objects.
• Extensors are attached to the back of the spine.

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MUSCLES OF THE BACK

• Most of the body weight lies anterior to the
  spinal column.
• So the axis of gravity descends anterior to the
  vertebral column, knee and ankle.
• The deep muscles of the back are important in
  maintaining the spinal alignment and the normal
  postural curves of the spinal column in the
  standing position.
• There are 3 groups of muscles in the back
• Superficial muscles associated with the shoulder
  girdle.
• Intermediate muscles involved in respiration.
• Deep muscles belonging to the spinal column.

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SUPERFICIAL MUSCLES

• The superficial muscles belong to the upper limb.
  
• These are
• Trapezius
• Latissimus dorsi
• Levator scapulae
• Rhomboids minor
• Rhomboids major

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INTERMEDIATE MUSCLES

• The intermediate muscles are associated with
  respiration.
• These are
• Serratus posterior superior.
• Serratus posterior inferior.
• Levatores costarum.

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DEEP MUSCLES

• The deep muscles of the back form a deep, broad
  muscular column, which occupies the hollow on
  each side of the spinous processes.
• They extend from the sacrum to the skull.
• This muscle mass is composed from many small
  muscles of different length.
• Each individual muscle causes one or several
  vertebrae to be extended or rotated on the
  vertebra below.

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CLASSIFICATION OF THE DEEP MUSCLES OF THE BACK

• Superficial vertically running muscles
• Erector spinae
• Iliocostalis
• Longissimus
• Spinalis
• Intermediate oblique running muscles
• Transversospinalis
• Semispinalis
• Multifidus
• Rotatores
• Deepest muscles
• Interspinalis
• Intertransversarii

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BLOOD AND NERVE SUPPLY

• Arterial supply Dorsal branches of the posterior
  intercostal arteries.
• Venous drainage Posterior intercostal veins.
• Nerve supply Posterior rami of the spinal nerves

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Misalignment

• Back muscles stabilize your spine.
• Poor muscle tone or a large belly can pull your
  entire body out of alignment.
• Misalignment puts incredible strain on the spine.

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Facet joints

• The facet joints of the spine allow spinal
  motion.
• Each vertebra has four facet joints,
• One pair that connects to the vertebra above
  (superior facets)
• One pair that connects to the vertebra below
  (inferior facets).

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Ligaments

• The ligaments are strong fibrous bands that hold
  the vertebrae together, stabilize the spine, and
  protect the discs.
• The three major ligaments of the spine are
• Anterior longitudinal ligament (ALL),
• Posterior longitudinal ligament (PLL).
• The ALL and PLL are continuous bands that run
  from the top to the bottom of the spinal column
  along the vertebral bodies.
• They prevent excessive movement of the vertebrae,
  and hold the vertebral bodies and discs together.
• Ligamentum flavum,
• The ligamentum flavum attaches between the lamina
  of all vertebrae.

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What Types of Vertebral Injuries May Occur?

• The two main types of injuries to the spinal
  bones (vertebrae) are fractures and dislocations.
  
• A fracture is a break to any part of the
  vertebra.
• A dislocation is when the vertebrae do not line
  up correctly or are out of place.
• These injuries may cause damage to the spinal
  nerves or the spinal cord.
• There are several types of fractures and
  dislocations that can occur.

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Compression fracture

• This usually results from a hyperflexion (front
  to back) injury where part of the vertebral
  column is forced forward and downward.

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Burst Fracture

• A burst fracture is a very serious form of
  compression fracture.
• In this type the bone is shattered from the
  injury.
• Bone fragments may pierce the spinal cord.
• The injury usually occurs from a downward or
  upward force along the spine.
• It is often result in serious spinal cord injury.

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Subluxation

• In subluxation, the joints in the back of the
  vertebrae are weakened by abnormal movement of
  the bones.
• It is a partial dislocation of the vertebrae.
• It happens if the muscles and ligaments in the
  spine are injured.
• It may also cause injury to the spinal cord. 

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Dislocation

• A dislocation also may occur when ligaments are
  badly stretched from the injury.
• This allows too much movement of the vertebrae.
• The vertebrae may "lock" over each other on one
  or both sides.
• A spinal cord injury may occur, depending on how
  much extra movement is allowed by the torn
  ligaments.
• The vertebrae that are not lined up correctly are
  returned to a normal position by a "reduction".
  Traction or surgery is often required for a
  reduction.
• A brace, vest, or surgery to fuse the vertebrae
  is sometimes needed to keep the vertebrae lined
  up correctly.

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Fracture- Dislocation

• This occurs when there is a fracture and a
  dislocation of the vertebrae.
• There is usually serious ligament and soft tissue
  injury and this may also cause injury to the
  spinal cord

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