1. Comprehensive Review Cranial Mechanics
Darlene Myles D.O.
Block 8

2. Objectives Review Cranial anatomy
Describe the basic components of the Cranial concept
Describe the major axes of motion in the Cranial base and vault
Describe motion mechanics of the Cranium
Review SBS strain patterns
Review visual diagnosis of SBS strain patterns

3. Primary Respiratory Mechanism (PRM)
5 Components to Model
Motility of CNS
Fluctuation of CSF
Mobility of intracranial / intraspinal membranes (reciprocal tension)
Articular mobility of cranial bones
Involuntary motion of sacrum between ilia
Will be on the test

4. 5 poles of attachment of the Dural Membrane
Anterior-superior pole
The falx attaches to the cristi galli of the ethmoid and to the frontal crest
Anterior-inferior pole
The tentorium attaches to the anterior and posterior clinoid processes of the sella turcica
Lateral poles
The tentorium attaches to the petrous ridge of the temporal bone and the transverse ridge of the occiput
4. Posterior pole
The internal occipital protuberance (opisthion)
5. Sacral pole
The dura exits the foramen magnum attaches to C2 and then hangs loosely until it attaches to the S2 sacral segment
Know where the points of attachment are

5. Primary Respiratory Mechanism (PRM)
Expansion and Contraction of the CNS discussed in relation to what happens at the major keystone joint of the Cranial mechanism (The SBS)
During the expansion phase the SBS Flexes
During the Contraction Phase the SBS Extends
Know the SBS is the joint where everything works around

6. SBS Sphenobasilar Synchondrosis
All movement and strain is around the SBS
Know what SBS stands for and where it is

7. Axes of Motion for Sphenoid and Occiput
AP Axis ( 1 axis)
From Nasion through SBS to Opisthion
Vertical Axes (2 axes)
Through Foramen Magnum of the Occiput
Through Body of the Sphenoid
Transverse Axes ( 2 axes)
Just above the Jugular Process on a level with the SBS
Know where these axes are, not necessarily what each axis good.

8. Flexion
Sacrum moves posterior = counternuation

9. Extension
Sacrum moves anterior = nutation

10. Cranial Bone Motion
Each individual bone in the cranium has a predictable motion based on bevel changes
All Midline individual bones are said to either Flex or Extend around a transverse axis
All Paired bones are said to either internally rotate or externally rotate
During Flexion Phase all midline bones Flex
During Flexion Phase all paired bones Externally Rotate
During Extension phase all midline bones Extend
During Extension phase all paired bones Internally Rotate
Def know this
She said there will be a question on this

11. Articular … Cranial Bones - Sphenoid
Transverse axis through the center of its body is in the area of the sella turcica
Vertical Axis through the center of its body is in the area of the sella turcica
AP Axis through the center of its body is in the area of the sella turcica AP Axis
The motion of the sphenoid occuring in the sagittal plane described as flexion and extension
Flexion:
Posterior aspect of the body elevates.
The sella turcica moves anterosuperiorly.
Greater wings move forward and slightly laterally and inferiorly.
The pterygoids move posteriorly and inferolaterally.
The body expands a little as it carries the resistance of the facial bones.
Primarily influences ethmoid, vomer and facial bones
Adapted from a lecture by Barry Malina, D.O., F.A.A.F.P. – AZCOM
Know that the sphenoid primarily influences ethmoid, vomer and facial bones  test question
-she also said this is all you need to know from this slide and for boards as well

12. Articular … Cranial Bones - Occiput
Occipital Motion
The occiput has physiologic motion of flexion & extension
in the sagittal plane around a transverse axis, lying just above the jugular processes.
Flexion
- the occipital base moves superiorly
- the posterior aspect moves posterior-inferiorl
- the occipital condyles move anteriorly.
The occiput primarily influences the parietals & temporal bones.
Adapted from a lecture by Barry Malina, D.O., F.A.A.F.P. – AZCOM
Know that the occiput primarily influences the parietals & temporal bones  question
-she also said this is all you need to know from this slide and for boards as well

13. Articular … Cranial Bones – Temporal
The motion of the occiput is directly responsible for the motion of the temporal bones.
The axis of physiologic motion runs from the jugular surface to the petrous apex parallel to the petrous ridge.
In the flexion phase, the temporal bones externally rotate. The squama moves anterolaterally and the mastoid portion moves medially and slightly posteriorly.
In the extension phase, the reverse occurs
External Rotation Internal Rotation
Adapted from a lecture by Barry Malina, D.O., F.A.A.F.P. – AZCOM
Meh, only know what is in red

14. Articular Mobility of Cranial Bones

15. Articular … Cranial Bones - Frontal
Axis of rotation runs from the center of the orbital plate up through the center of the orbital eminence near the change of bevel at the cranial border. Hinge-like action along the metopic suture, remains a line of persisting flexibility.
In external rotation, the inferior lateral angles (zygomatic angles) of the frontal bone move laterally, inferiorly and slightly forward. The opposite occurs in internal rotation.
The glabella tends to recede slightly in external rotation due to the pull of the falx cerebri.
Adapted from a lecture by Barry Malina, D.O., F.A.A.F.P. – AZCoM
Know both the frontal and parietal bones are paired

16. Articular … Cranial Bones - Parietal
Axis runs parallel to the sagittal suture through the change of bevel at the anterior & posterior borders of each parietal bone
In external rotation, the inferior borders of the parietal bone moves laterally. A “widening” occurs which is greatest at the posterior aspect of the bones. Internal rotation the inferior borders move medially.
Adapted from a lecture by Barry Malina, D.O., F.A.A.F.P. – AZCOM
Know both the frontal and parietal bones are paired

17. Parietal
In flexion, paired bones (like the parietal bone) will externally rotate  this will widen the head and shorten the AP diameter
In Extension, paried bones (like the parietal bone) will internally rotate  this will lengthen the AP diameter, making the head less wide

18. Motions of Flexion and Extension
Midline Bones Flex
Paired bones externally rotate
Bi-parietal diameter increases
AP diameter decreases
Midline bones extend
Paired bones internally rotate
Bi-parietal diameter
decreases
AP diameter increases
Test questions will come from this slide
This basically summarizes a bunch of slides so far

19. A few key relationships
Osteology
A few key relationships

20. These four bones overlap in alphabetical order from within outward
Pterion
These four bones overlap in alphabetical order from within outward
Netter Presenter: 2001.
Frontal - anterosuperiorly
Parietal – posterosuperiorly
Sphenoid –lateral surface of great wing, anteroinferiorly
Temporal - centrally
Frontal
Parietal
Temporal
Sphenoid
This was a test question before, it will probably be a test question again
Know which four bones overlap to form the pterion
Know where the pterion is if given a pic

21. Pterion

22. Strain Patterns
Patterns of the SBS

23. Strain Patterns Flexion Extension Torsion Side Bending Rotation
Right
Left
Side Bending Rotation
Lateral Strain
Vertical Strain
Superior Strain
Inferior Strain
Compression

24. Physiologic Strain Patterns of SBS
Flexion
Extension
Torsion
Right
Left
Side Bending Rotation
Know what of the strain patterns are physiological  test question

25. Flexion - Extension Are the expected physiologic motions
Can be pathological if restricted in one extreme or another

26. Flexion/extension
Longer than usual cycle, typically (Similar to prolonged exhalation in COPD)
Will have different feels at the ‘endpoints’ of the phases
Will have decreased flow in the opposite phase (e.g., flexion dysfunctions will have diminished extension pattern)
Extension
Flexion
Flexion, SBS moves up, tension is cephlad of dural sheath, sacrum will move posterior, midline bones flex, paired bones externally rotate, AP diameter shortens.
Extension is opposite of all of this
This is no different than a normal physiological motion, it is just one way moves way better than the other, therefore you have a dysfunction

27. FLEXION

28. EXTENSION

29. Flexion ER ER ER ER Findings-all quadrants in external rotation
Increased transverse diameter
Forehead wide and sloping(brow prominent with forehead receding)
AP diameter equal on both sides
Sagittal suture flattened or depressed
Sphenoid
Superomedial-inferolateral diameter greater
Orbits wider
Eyeballs protuberant
Increased fronto-zygomatic angle
Frontal processes of maxillae are nearly in coronal plane
Maxillary palantine processes flattened
Occiput
Protruding ears
Mastoid tips posteromedial
Maxillae
Nasolabial crease deeper
This is retarded.
Just know what their face looks like with a flexion dysfunction and ignore that stupid circle

30. Extension IR IR IR IR Findings-all quadrants in internal rotation
Long narrow head
Decreased transverse diameter
Forehead prominent with Brow receding
Sphenoid
Superomedial-inferolateral diameter decreased
Decreased frontozygomatic angle
Orbit narrowed
Eyeballs retruded
Frontal processes of the maxillae are nearly in sagittal plane
Maxillary palantine processes arched
Occiput
Ears close to head
Mastoid tips anterolateral
Maxillae
Nasolabial crease shallow
This is retarded too
Again, just know what their face looks like with an extension dysfunction and ignore that stupid circle

31. TORSION One axis Antero-superior to Infero-posterior
Spenoid and occiput rotate in opposite directions
Named for superior great wing of sphenoid
Just know it is on an AP axis and you name it for the wing of the sphenoid that is higher

32. Torsion
Torsion of the sphenoid about an anteroposterior (AP) axis extending from the nasion through the symphysis to opisthion
The sphenoid & anterior skull components are in one direction, the occiput & posterior components in the other.
This strain is named for the side of the high wing of the sphenoid, right torsion (RT) or left torsion (LT)

33. Right Torsion IR ER IR ER Findings- asymmetric quadrants
Sphenoid-1 quadrant in external rotation
Higher greater wing side relative to the other
Orbit wide
Frontolateral angle anterior
Zygomatic orbital rim everted
Maxillary frontal processes in more coronal plane
Maxillary palantine processes flattened
Occiput-1 quadrant in external rotation
Low occiput side relative to the other
Protruding ears
Mastoid tips posteromedial
This pic for ex would be a right torsion
Nothing else on this slide is prob relevant at our level

34. SIDEBENDING ROTATION Two axes: A-P and bilateral vertical axes
Occiput and Sphenoid rotate same direction on AP axis; side-bend away from each other on parallel vertical axes.
Named for convexity

35. Sidebending – Rotation Strain
Occurs around an AP axis & around 2 parallel vertical axes: one through the body of the sphenoid & one through the foramen magnum, perpendicular to the physiologic transverse axes & the A-P axis
As the SBS sidebends, it also rotates inferiorly to the convex sidebending side (coupled motion)
Named for the convex side of sidebending
Lt Sidebending – Rotation Strain

37. Right Sidebending RotationER IR IR ER
Findings- 1 side of face full and convex with the opposite side flattened (side of the lower greater wing of the sphenoid)
Sphenoid-
Side of low greater wing in internal rotation
Lateral fontal angle posterior
Orbit narrower
Eyeball retruded
Frontozygomatic angle lessened
Zygomatic tuberosity prominent
Maxillary frontal process more sagittal
Maxillary palantine process more arched
Occiput
Mastoid tip –posteromedial
Ear protruding
Meh

38. Non-physiologic Strain Patterns of SBS
Lateral Strain
Right
Left
Vertical Strains
Superior Strain
Inferior Strain
Compression
Know these types of strains are non physiological  test question

39. LATERAL STRAIN Bilateral vertical axes
Shearing force at SBS causing Sphenoid and Occiput to rotate same direction on axes
Named for position of basisphenoid
Head appears “parallelogram”

40. Lateral Strain
Sphenoid and occiput have the same rotation about a vertical axis, resulting in a lateral strain pattern
Can happen with a one-sided impact from the front or back of head (off-center impact)
Named for the position of the base of the sphenoid, relative to the occiput at the SBS
Also known as “parallelogram head”
Left lateral strain
KNOW that it is caused by a one sided impact (off centered) and that it is called a parallelogram head

41. VERTICAL STRAINS
Sphenoid and Occiput rotate same direction on parallel horizontal axes
Named for position (superior/inferior) of base of Sphenoid

42. Vertical Strain -Superior/Inferior
Sphenoid and occiput have the same rotation about a transverse axis, resulting in a vertical strain pattern
Named for the position of the base of the sphenoid, relative to the occiput at the SBS
Superior Shear
Inferior Shear
Superior Shear

43. SBS Compression Aka, ‘bowling ball head’
This is where the SBS has been compressed (think of a ‘jammed’ finger), causing a near total lack of motion at the SBS in any particular direction
Most commonly seen in frontal impact trauma, difficult births, and circumferential loads to the skull, but can also be seen in severe psychiatric & emotional states

44. SBS Patterns Axes Naming A-P Transverse Vertical Paired
SB-Rot=Convexity
Torsion=High Gr Wing
Rest=Sphenoid Base Direction

45. Overview of Motions Occiput, sphenoid, ethmoid, vomer
Rotate about a transverse axis during physiologic Flexion and Extension
Paired bones of the periphery
Frontals, temporals, parietals, maxilla, palatines, zygomae
Rotate externally during cranial flexion
Rotate internally during cranial extension

46. Observational Diagnosis
Flexion
Extension
Torsion
Sidebending Rotation
Observational diagnosis
Observe face from the frontal and from superior view of the head
Know what is in red  could be a test question

47. Picture Effect on Internal/External Rotation on Paired Bones of Face
Easiest: Flexion or Extension Type
Palate/Dental Arch:
Extension = high & narrow
Flexion = low & wide
Face affected most by Sphenoid; Temporals & Sacrum by Occiput

48. Diagnosis by Visual Observation
Flexion
Extension
Orbit widens/ protrudes
Nasolabial crease deeper
Flattened Cheek
Ears – outflared
Decreased Frontal Eminence
Sloping forehead
Prominent Brow/Superciliary ridge
Orbit narrows/ recedes
Nasolabial crease shallow
Cheek prominent
Ears- inflared
Increased Frontal Eminence
Vertical forehead
Receding Brow/Superciliary Ridge

49. Vault Hold
Pt supine, you gently place your hands on the lateral aspects of the cranium with the following landmarks:
Index fingers in the temple (not temporal) region, over the greater wings of sphenoid
Middle finger just in front of the ear on the temporal bone
Ring finger just behind the ear on the temporal bone
Little finger as close to the mastoid portion of the occipitomastoid suture as possible
Thumbs gently resting on parietals or frontal bone, wherever they fall for your hands on the patient’s skull

50. Flexion
Shortening with flexion

51. Extension
Elongation with extension

52. Fronto-Occipital Hold
Patient supine, with head at 3/4 of table.
Physician at side of head of table.
One hand cupping occiput.
Other hand lightly palpating frontal bone
General sensation is that of:
Shortening of A/P axis with Flexion
Elongation of A/P axis with Extension
Meh, not impt

53. Flexion = Shortening of A/P axis Extension = Lengthening of A/P axis

54. Temporal Bone as “Trouble-Maker”
External
Rotation of
Temporal =
Pressure on
Trigeminal
Ganglion &
Tightens Cave

55. Cranial Nerves - Summary
Temporal Bone as “Trouble-Maker”
For all the cranial nerves, know what their name is and know what the do
CN 11 definitely goes through the foramen magnum….not the jugular formamen
CN 1 – cribiform plate
CN 2 – optic canal (not foramen)
V2 – foramen rotundum
V3 – foramen ovale
CN V1, 3,4,6  all through superior orbital fissure

56. Olfactory Nerve - CNI Hx: Blow to head Anosmia Altered sense smell
Physical:
Ability to smell
Frontal bone motion
Also sphenoid, ethmoid, vomer motion
Tx of Dysfunction: Frontal lift – Ethmoid pump OMT

57. Motor to Extra-Ocular Ms’s
CN III, IV, VI Group:
Motor to Extra-Ocular Ms’s
III: Parasympathetic
(Accommodation)

58. Petrosphenoidal Ligament and its association with CN III, IV, VI
Attached border of Tentorium
“Petrosphenoidal Ligament”
(Ligamentous thickening from end of Petrous Temporal to Sphenoid)
CN III over;
CN IV through;
CN VI under & at tip of the temporal
She will not ask this
External
Rotation

59. CNV - Trigeminal Sensory to the Face
Function
Structure
Dysfunction
History
Physical examination
Sensory to the Face
Motor to the muscles of mastication
V1=SOF, V2=Foramen rotundum, V3=Foramen ovale; Meckel’s cave, petrosphenoid ligaments, Cervical spine
Anesthesia, Trigeminal neuralgia (“Tic douleroux”)
Trauma, Plagiocephaly
Test sensation, corneal reflex
Evaluate temporal (petrobasilar), sphenoid

60. CN VII - Facial Nerve Motor to facial muscles Function
Parasympathetic to glands
Special sense to tongue
Stylomastoid foramen internal acoustic meatus
Paralysis, weakness, no or poor taste sense
Viral illness, trauma
Test facial expression, taste
External rotation of temporal and sphenoid bones
Function
Structure
Dysfunction
History
Physical examination
Bells palsy

61. CN VIII - Vestibulocochlear Nerve
Function
Structure
Dysfunction
History
Physical examination
Sensory - hearing and balance
Internal acoustic meatus
Hearing deficit, tinnitus, vertigo, otitis media and interna
Trauma, infectious diseases
Evaluation of temporals & sphenoid; balance; hearing

62. CN IX - Glossopharyngeal Nerve
Function
Structure
Dysfunction
History
Physical examination
Motor to muscle; Parasympathetic to glands; Sensory to palate
Jugular foramen
Difficulties swallowing, excessive gag reflex
Trauma to occiput &/or temporals
Test gag reflex
Evaluation of temporals, occiput, occipitomastoid suture

63. CN X - Vagus Nerve Function Structure Dysfunction History
Motor to striated muscle; Parasympathetic to smooth muscle and glands; Sensory from viscera
Jugular foramen, Foramen magnum
Numerous Somatovisceral; Posterior Headaches; More
Trauma occiput, temporal
Test gag reflex
Evaluate OA, AA, C2, temporal, occiput, OM suture
Function
Structure
Dysfunction
History
Physical examination

64. CN XI - Accessory Nerve

65. CN XI - Accessory Nerve Motor Function
Cervicals, Foramen magnum, Jugular foramen
Weakness/paralysis, torticollis; Recurrent Trigger Points in SCM & Trapezius
Trauma to cervicals, occiput, temporals
Test SCM & Trapezius muscles; Evaluate cervicals, occiput, temporals
Function
Structure
Dysfunction
History
Physical exam

66. CN XII - Hypoglossal Nerve
Function
Structure
Dysfunction
History
Physical examination
Motor to Tongue
Hypoglossal canal
Dysphagia, tongue function
Trauma to occiput (condyles)
Test tongue motions
Evaluate occiput (condyles), upper cervicals

67. Questions?