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Chapter 22
Craniovertebral Junction
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
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.
Anatomy

The occipito-atlantal (O-A) joint is
formed between the occipital
condyles, and the superior articular
facets of the atlas (C 1)
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
Anatomy

The superior-lateral aspect of each of
the posterior arches has a transverse
foramen to accommodate the vertebral
artery
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
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.
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
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
Anatomy

Ligaments
– Nuchal
– Transverse
– Alar and accessory alar
– Apical
– Vertical and transverse bands of the
cruciform
– Capsule and accessory capsular ligaments
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
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
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
Anatomy

Vertebral artery
– Supplies the most superior segments of
the cervical spinal cord
Anatomy

Muscles
– Deep

Posterior suboccipitals
Biomechanics

O-A Joint
– The primary motion that occurs at this
joint is flexion and extension, although
side bending and rotation also occur
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)
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.

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

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
Biomechanics

The biomechanics of this region are
exploited using the differentiation test
to help determine the segment
involved
Examination

History
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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)
Examination

Systems review
– The craniovertebral region houses many
vital structures:
The spinal cord
 The vertebral artery
 The brain stem

Examination

Systems review
– Periodic loss of consciousness
– Dysphasia
– Diplopia
– Hemianopia
– Ataxia
– Hyperreflexia
– Babinski response
Examination

Systems Review
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Positive Hoffman or Oppenheim test
Flexor withdrawal
Nystagmus
Quadrilateral paresthesia
Bilateral upper limb paresthesia
Peri-oral anesthesia
Drop attacks
Wallenberg syndrome
Examination

Tests and measures
– AROM
– Passive overpressure
– Isometric resistance

If the patient is able to flex their neck,
a C-V fracture or a transverse ligament
compromise can be provisionally ruled
out

Much more a function of the lower
cervical spine, side bending is
nonetheless significantly decreased in
cases of craniovertebral instability or
articular fixation
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
Loss of Rotation

Serious causes:
– Fracture (Dens, Hangman’s)
– Muscle splinting
– Rotation is the most likely (single) motion
to bring on VA signs or symptoms
Loss of rotation

Biomechanical causes
– A loss of rotation associated with pain
and a history of recent trauma could
indicate an acute/sub-acute, posttraumatic arthritis
– A loss of rotation associated without pain
and a history of chronic trauma could
indicate a chronic, post-traumatic arthritis
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
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

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

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 AA joint not the O-A joint
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
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
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
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
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
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
Examination

Segmental stability tests. The C-V
junction is stressed in the following
directions:
– Longitudinal (traction)
– Anterior (transverse ligament)
– Coronal (alar)
– Transverse (articular)
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
Examination

Special tests
– Vertebral artery tests
– Vestibular tests
– Sharp-Purser test
Examination

Other tests that can be used:
– Palpation
– Positional tests
– Uni-planar passive physiological mobility
tests
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
Intervention

The structure at fault should determine the
intervention:
– If ligamentous tissue damage or an intraarticular 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
Intervention
– Contractile tissue. Within the patient’s
pain tolerance, contractile lesions should
be treated aggressively with the emphasis
on regaining maximal muscle length
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

Intervention

Functional phase
– The goals of this phase are:
To significantly reduce or to resolve the
patient’s 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
