Craniovertebral Junction

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Chapter 22

• Craniovertebral Junction

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Overview

• The craniovertebral (CV) junction is a collective
  term that refers to the occiput, atlas, axis, and
  supporting ligaments
• Accounts for approximately 25 of the vertical
  height of the entire cervical spine

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Anatomy

• Foramen magnum
• The smaller anterior region of the foramen magnum
  is characterized by a pair of tubercles to which
  the alar ligaments attach.
• The posterior portion of the foramen magnum
  houses the brainstem-spinal cord junction.
• The demarcation of these two regions is marked by
  a pair of tubercles to which the transverse
  ligament of the atlas attaches.

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Anatomy

• The occipito-atlantal (O-A) joint is formed
  between the occipital condyles, and the superior
  articular facets of the atlas (C 1)

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Anatomy

• The Atlas
• The atlas (C 1) is a ring-like structure that is
  formed by two lateral masses, which are
  interconnected by anterior and posterior arches
• Since this vertebra does not have a spinous
  process, there is no bone posteriorly between the
  occipital bone and the spinous process of C 2

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Anatomy

• The superior-lateral aspect of each of the
  posterior arches has a transverse foramen to
  accommodate the vertebral artery

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Anatomy

• Axis (C 2)
• The axis serves as a transitional vertebra
  between the cervical spine proper and the
  craniovertebral region
• A unique feature of the axis, the odontoid
  process, or dens is located on its superior
  aspect
• The dens extends superiorly from the body to just
  above the C 1 vertebra, before tapering to a
  blunt point

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Anatomy

• The dens functions as a pivot for the upper
  cervical joints, and as the center of rotation
  for the A-A joint.
• The anterior aspect of the dens has a hyaline
  cartilage covered mid-line facet for articulation
  with the anterior tubercle of the atlas (the
  median A-A joint).
• The posterior aspect of the dens is usually
  marked with a groove where the transverse
  ligament passes.

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Anatomy

• The atlanto-axial (A-A) joint is a relatively
  complex articulation
• Two lateral zygapophysial joints between the
  articular surfaces of the inferior articular
  processes of the atlas, and the superior
  processes of the axis
• Two medial joints one between the anterior
  surface of the dens of the axis, and the anterior
  surface of the atlas, and the other between the
  posterior surface of the dens and the anterior
  hyalinated surface of the transverse ligament

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Anatomy

• Supporting structures
• In the absence of an intervertebral disk (IVD) in
  this region, the supporting soft tissues of the
  joints of the upper cervical spine must be lax to
  permit motion, while simultaneously being able to
  withstand great mechanical stresses

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Anatomy

• Ligaments
• Nuchal
• Transverse
• Alar and accessory alar
• Apical
• Vertical and transverse bands of the cruciform
• Capsule and accessory capsular ligaments

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Anatomy

• Nuchal ligament
• A bilaminar fibroelastic and intermuscular septum
  that spans the entire cervical spine
• Extends from the external occipital protuberance,
  to the spinous process of the seventh cervical
  vertebra
• When the O-A joint is flexed, the superficial
  fibers tighten and pull on the deep laminae,
  which in turn, pull the vertebrae posteriorly,
  limiting the anterior translation of flexion and,
  therefore, flexion itself

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Anatomy

• Transverse ligament
• The major responsibility of the transverse
  portion of the cruciform ligament is to
  counteract anterior translation of the atlas
  relative to the axis, thereby maintaining the
  position of the dens relative to the anterior
  arch of the atlas
• The transverse ligament also limits the amount of
  flexion between the atlas and axis

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Anatomy

• Alar ligaments
• The alar ligaments connect the superior part of
  the dens to fossae on the medial aspect of the
  occipital condyles, although they can also attach
  to the lateral masses of the atlas
• Function to resist flexion, contralateral side
  bending and rotation of the neck

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Anatomy

• Vertebral artery
• Supplies the most superior segments of the
  cervical spinal cord

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Anatomy

• Muscles
• Deep
• Posterior suboccipitals

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Biomechanics

• O-A Joint
• The primary motion that occurs at this joint is
  flexion and extension, although side bending and
  rotation also occur

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Biomechanics

• A-A Joint
• The major motion that occurs at all three of the
  A-A articulations is axial rotation, totaling
  approximately 40 to 47 to each side
• Flexion and extension movements also occur
  amount to a combined range of 10-15º (10º of
  flexion, and 5º of extension)

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Biomechanics

• The direction of the conjunct motion appears to
  be dependent on the initiating movement
• If the initiating movement is side bending
  (latexion), the conjunct rotation of the joint is
  to the opposite side
• If the initiating movement is rotation
  (rotexion), the conjunct motion (side bending) is
  to the same side.

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• Side bending of the head to the right produces
• Left rotation of the O-A joint, accompanied by a
  translation of the occiput to the left
• Left rotation of the A-A joint
• Right rotation of C 2-3

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• During rotation of the head to the right
  (rotexion)
• Right side bending and right rotation occur at
  the A-A joint and at C 2-3
• Left side bending and right rotation occur at the
  O-A joint, accompanied by a translation to the
  right

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Biomechanics

• The biomechanics of this region are exploited
  using the differentiation test to help determine
  the segment involved

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Examination

• History
• Headaches
• Jaw, facial or eye pain (see Systems review)
• Ear pain or middle ear symptoms (tinnitus)
• Dizziness
• Paresthesia of the tongue, face or head
• Tongue sensitivity changes (e.g., acidic,
  metallic tastes)

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Examination

• Systems review
• The craniovertebral region houses many vital
  structures
• The spinal cord
• The vertebral artery
• The brain stem

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Examination

• Systems review
• Periodic loss of consciousness
• Dysphasia
• Diplopia
• Hemianopia
• Ataxia
• Hyperreflexia
• Babinski response

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Examination

• Systems Review
• Positive Hoffman or Oppenheim test
• Flexor withdrawal
• Nystagmus
• Quadrilateral paresthesia
• Bilateral upper limb paresthesia
• Peri-oral anesthesia
• Drop attacks
• Wallenberg syndrome

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Examination

• Tests and measures
• AROM
• Passive overpressure
• Isometric resistance

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• If the patient is able to flex their neck, a C-V
  fracture or a transverse ligament compromise can
  be provisionally ruled out

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• Much more a function of the lower cervical spine,
  side bending is nonetheless significantly
  decreased in cases of craniovertebral instability
  or articular fixation

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Rotation

• Neck rotation is considered as the functional
  motion of the craniovertebral joints
• If symptoms are not reproduced with neck
  rotation, it is doubtful whether a
  craniovertebral dysfunction is present

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Loss of Rotation

• Serious causes
• Fracture (Dens, Hangmans)
• Muscle splinting
• Rotation is the most likely (single) motion to
  bring on VA signs or symptoms

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Loss of rotation

• Biomechanical causes
• A loss of rotation associated with pain and a
  history of recent trauma could indicate an
  acute/sub-acute, post-traumatic arthritis
• A loss of rotation associated without pain and a
  history of chronic trauma could indicate a
  chronic, post-traumatic arthritis

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Loss of rotation

• To differentiate the potential biomechanical
  causes for the loss of rotation, the following
  tests are used
• Combined motion testing (No H and I or Figure of
  8 in this region)
• Relevant passive glide delivered at the end of
  range for end-feel or pain reproduction
• Linear/planar segmental stress tests

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Combined motions

• Flexion and extension at the O-A joints involves
  anterior-posterior gliding of the occipital
  condyles
• The same gliding (although reciprocal in opposing
  facets) is utilized in rotation

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• Therefore, if a symptom or range of motion is
  drastically altered by adding craniovertebral
  flexion or extension an assumption could be made
  that the dysfunction is at the O-A joint not the
  A-A joint

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• Similarly, if a symptom or range of motion is not
  drastically altered by adding craniovertebral
  flexion or extension an assumption could be made
  that the dysfunction is at the A-A joint not the
  O-A joint

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Example

• The RIGHT O-A joint cannot flex (i.e., the right
  occipital condyle cannot glide posteriorly)
• The predominant functional loss will be decreased
  RIGHT rotation
• The restriction of RIGHT rotation will increase
  with C-V flexion
• However, The restriction of RIGHT rotation will
  decrease (be less obvious) with C-V extension

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Example

• The RIGHT O-A joint cannot extend (i.e., the
  right occipital condyle cannot glide anteriorly)
• The predominant functional loss will be decreased
  LEFT rotation
• The restriction of LEFT rotation will increase
  with C-V extension
• However, The restriction of LEFT rotation will
  decrease (be less obvious) with C-V flexion

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Relevant passive joint glide

• Example
• If it was determined in the combined motion
  testing that the RIGHT O-A joint is more
  restricted or painful with flexion
• The joint is taken to the limit of its range of
  motion i.e., right rotation in flexion (the two
  motions associated with a posterior glide of the
  right O-A joint) and the end feel is assessed

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Relevant passive joint glide

• Example
• If it was determined in the combined motion
  testing that the RIGHT O-A joint is more
  restricted or painful with extension
• The joint is taken to the limit of its range of
  motion i.e., left rotation in extension (the two
  motions associated with an anterior glide of the
  right O-A joint) and the end feel is assessed

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End feel

• End feel assessment
• Firm end feel, with or without pain may require
  mobilization/muscle energy depending on findings
  at contralateral joint
• Loose end feel, with pain is more suggestive of a
  hypermobility/instability need to perform
  stability tests

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Examination

• The craniovertebral region demonstrates a high
  degree of mobility, but little stability
• Some stability is provided by the ligaments,
  although they afford little protection during a
  high velocity injury

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Examination

• Segmental stability tests. The C-V junction is
  stressed in the following directions
• Longitudinal (traction)
• Anterior (transverse ligament)
• Coronal (alar)
• Transverse (articular)

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Examination

• Neurological tests
• Cervical myelopathy, involving an injury to the
  spinal cord itself is associated with
  multi-segmental paresthesias, upper motor neuron
  (UMN) signs and symptoms such as spasticity,
  hyperreflexia, visual and balance disturbances,
  ataxia, and sudden changes in bowel and bladder
  function

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Examination

• Special tests
• Vertebral artery tests
• Vestibular tests
• Sharp-Purser test

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Examination

• Other tests that can be used
• Palpation
• Positional tests
• Uni-planar passive physiological mobility tests

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Examination

• Palpation
• Asymmetrical joint geometry is common in this
  region
• Examination of the skin overlying the spine has
  been found to be very helpful as certain skin
  changes in a particular location may point in the
  direction of a dysfunctional spinal area
• Palpation can be performed at any time during the
  examination or as a separate entity

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Intervention

• The structure at fault should determine the
  intervention
• If ligamentous tissue damage or an
  intra-articular lesion is suspected the safest
  initial approach would be to help in unloading
  the joint and controlling the extremes of motion
  with a soft collar
• Articular. Depending on the stage of healing, an
  initial (10-14 day) resting/immobilization
  period, followed by a progressively increasing
  mobilization / activation program

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Intervention

• Contractile tissue. Within the patients pain
  tolerance, contractile lesions should be treated
  aggressively with the emphasis on regaining
  maximal muscle length

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Intervention

• Acute phase
• The goals of this phase include
• Reduce pain, inflammation and muscle spasm
• Reestablish a non-painful range of motion
• Improve neuromuscular postural control
• Retard muscle atrophy
• Promote healing

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Intervention

• Functional phase
• The goals of this phase are
• To significantly reduce or to resolve the
  patients pain
• Restore full and pain-free range of motion
• Fully integrate the entire upper kinetic chain
• Restore full cervical and upper quadrant strength
  and neuromuscular control