Cranial strains Flashcards
Physiologic motion of midline bones
Midline bones: spehnoid, occiput, ethmoid (medial plate), vomer, and sacrum
Flexion and extension phases
Physiologic motion of paired bones
Paired bones: temporals, parietals, frontals, ethmoid (lateral mass), nasals, lacrimals, maxillae, palatines, zygomae, inferior conchae, and mandible
External and internal rotation phases
Physiologic motion
Flexion occurs with external rotation
Extension occurs with internal rotation
Reciprocal tension membrane
- Falx cerebri
- Tentorium cerebelli
Formed by dural reflections
Dura is contiguous with periosteum of skull, and extends throughout the spinal column creating link to sacrum and throughout the body
Creates a tensegrity model that guides motion
Sphenobasilar synchrondrosis (SBS)
All cranial motion at the SBS is named for the motion of the basi-sphenoid on the basi-occiput
We are observing the motion of the basi-sphenoid on the basi-occiput through contact with:
- The greater wings of the sphenoid
- The lateral angles of the occiput
Vault hold
Hands are in such a position to be able to palpate and observe motion of the SBS through contact with the sphenoid and occiput
- Index fingers on greater wings of sphenoid
- Pinky fingers on the lateral angles of the occiput
(ear is in between middle and ring finger)
Enables the operator to feel the dysfunction in order to initiate treatment.
Treatment also begins with this hold
Cranial strains
- Flexion/extension: inherent motion of SBS but can still get SD
- Torsion: right or left
- Sidebending rotation: right or left
- Vertical strain: superior or inferior
- Lateral strain: right or left
- SBS compression
Physiologic strains
Physiologic strains are those normal compensatory patterns that happen in response to other motions of the body.
These are normal EXCEPT when the SBS gets stuck there. Causes SD.
- Flexion/extension
- Torsions
- Sidebending rotation
Flexion
Motion is rotational around 2 transverse axes:
- At level of foramen magnum
- Body of sphenoid
Motion occurs at SBS:
- Basioocciput and basisphenoid move cephalad
- Occipital squama and wings of spenoid move caudally
Extension
Motion is rotational around 2 transverse axes:
- At level of foramen magnum
- Body of sphenoid
Motion occurs at SBS:
- Basiocciput and basisphenoid move caudad
- Occiptal squama and wings of sphenoid move cephalad
Torsion
Sphenoid and occiput rotate in opposite directions around an AP axis
Named by the superior greater wing of the sphenoid… which is mirroring the motion of the basisphenoid.
EX: right greater wing superior and left occipital angle superior = right torsion
In the vault hold- one greater wing superior to the other AND the opposite occipital angle more superior than the others
Sidebending rotation
Sphenoid and occiput rotate around 2 sets of axes:
- To sidebend: opposite directions around parallel vertical axes
- To rotate: in the same direction around AP axis
Altogether this gives the sense of convexity and inferior motion on one side.
- Named for the side of the convexity (the side that gets fat) and inferior motion
Shadow hands
R SBS sidebending rotation:
- Right index and pinky fingers move inferiorly and spread apart slightly in comparison to the left
Non-physiologic strains
Strains that are never normal at the SBS. Usually happen in response to trauma
- Lateral strains/shears
- Vertical strains/shears
- SBS compression
Lateral strains
Sphenoid and occiput rotate in the same direction about parallel vertical axes resulting in a lateral shearing force at the SBS.
Named by the direction the basisphenoid moves.
- Basisphenoid and greater wings of ethmoid move in opposite directions.
In the vault hold, your hands will form a parallelogram.
- Index fingers will shift one direction, while the pink fingers shift in the opposite
Right lateral strain:
- Both index fingers shift left
- Both pinky fingers shift right
Vertical strains
Sphenoid and occiput rotate in the same direction on parallel transverse axes (as in flexion and extension)
One bone is in flexion while the other is in extension
Vertical strains are named by the direction of the basisphenoid: superior or inferior
In the vault hold, the index fingers will move in the opposite direction of the basisphenoid
- Superior vertical strain: wings down, base up
- Inferior vertical strain, wings up, base down
Shadow hands for lateral strains
Index fingers will move in the OPPOSITE direction of the basisphenoid
Index fingers move right, basi-sphenoid moves left = LEFT lateral strain
Index fingers go left, basisphenoid moves right= RIGHT lateral strain
Shadow hands for vertical strains
Index fingers will move in the OPPOSITE direction of the basisphenoid
Index fingers go inferiorly, basisphenoid moves superiorly = superior vertical strain
SBS compression
Approximation of the sphenoid and occipital bases as they compress together along the AP axis
In vault hold:
- Fingers of both hands approximate
- More commonly, bc this severly limits the resiliency of the SBS, flexion and extension are limited
- Often these heads will feel hard and generally limited in movement of any kind
Causes of cranial SD
- Birth trauma
- Intrauterine position
- Head trauma
- Falls on the buttock
- Surgical trauma
- SD from other areas of the body
- Viscero-somatic reflexes
Practice: R index and pinky fingers are superior to the L, while the index and pinky fingers on the L spread apart and move inferiorly.
Diagnosis?
Left sidebending rotation
Practice: index fingers shift L, pinky fingers shifted right
Diagnosis?
Right lateral shear
Practice: both index fingers move inferiorly, both pinky fingers move superiorly
Superior vertical strain
Practice: A patient comes in for evaluation after hitting her head on the ice while playing hockey. Osteopathic evaluation reveals minimal motion at the SBS. What is your cranial diagnosis
SBS compression
Perspective
When figuring out the cranial strain based on the vault hold, remember where your landmarks are in relationship to anatomical position of the patient.
Potential traumatic forces involved with superior vertical strain
- Caudal force applied centrally over the anterior- superior frontal bone.
- Force to the superior occiput (near lambda) and directed from superior/posterior to anterior
Potential traumatic forces involved with inferior vertical strain
- Caudal force transmited to the basisphenoid such as a caudal force transmitted from bregma.
- A cephalad force transmitted to the condylar parts such as a fall on the base of the spine (landing on the buttocks with a force transmitted up the spine)
- A caudal force transmitted over the bilateral posterior-superior parietal bones or along ht eposterior sagittal suture
Potential Traumatic Forces Involved in SBS compression
Force directed along the AP axis leading to longitudinal compression of the SBS. May originate at nasion or at opisthion
Potential Traumatic Forces involved in lateral strains
- Lateral to medial directed force applied over the greater wing of the sphenoid pushing the greater wings to the left or right (a medially directed force to the left greater wings will drive the basisphenoid to the opposite direction)
- Lateral to medial directed force applied over the occiput pushing the posterior aspect of the occiput left or right
