1. Craniovertebral Junction
Chapter 22
Craniovertebral Junction

2. 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

3. 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.

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

5. 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

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

7. 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

8. 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.

9. 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

10. 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

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

12. 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

13. 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

14. 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

15. Anatomy Vertebral artery
Supplies the most superior segments of the cervical spinal cord

16. Anatomy
Muscles
Deep
Posterior suboccipitals

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

18. 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)

19. 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.

20. 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

21. 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

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

23. 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)

24. Examination Systems review
The craniovertebral region houses many vital structures:
The spinal cord
The vertebral artery
The brain stem

25. Examination Systems review Periodic loss of consciousness Dysphasia
Diplopia
Hemianopia
Ataxia
Hyperreflexia
Babinski response

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

27. Examination Tests and measures AROM Passive overpressure
Isometric resistance

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

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

33. 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

34. 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

35. 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

36. 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

37. 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

38. 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

39. 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

40. 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

41. 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

42. 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

43. 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

44. 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

45. 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

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

47. 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

48. Examination Special tests Vertebral artery tests Vestibular tests
Sharp-Purser test

49. Examination Other tests that can be used: Palpation Positional tests
Uni-planar passive physiological mobility tests

50. 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

51. 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

52. Intervention
Contractile tissue. Within the patient’s pain tolerance, contractile lesions should be treated aggressively with the emphasis on regaining maximal muscle length

53. 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

54. 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