Physiologic strain patterns
Torsion and sidebending rotation.
Cranial torsion axis and rotation
occurs around 1 AP axis.
sphenoid and occiput rotate in opposite directions. orbit on the named side will be elevated.
Etiology of torsion
hit from above or below anterior quadrant (front or cheek). or hit from above or below the posterior quadrant (parietal or occipital).
Sidebending Rotation pattern axes and rotation
occurs around 3 axes (2 vertical, 1 AP)
sphenoid and occiput rotate in opposite directions around their parallel vertical axes. rotate same around AP axis.
etiology of sidebending rotation strain pattern.
vertical strains, lateral strains, SBS compression. do not occur during normal cranial motion. usually the result of trauma of some kind.
occurs around 2 horizontal axes. (sphenosqhamous, jugular process) named for the position of the body of the sphenoid relative to the base of the occiput.
- sphenoid and occiput rotate in the same direction around their axes
superior vertical strain
sphenoid is in flexion, occiput is in extension.
cause: result of a downward blow posterior to the SBS or an upward blow anteiror to the SBS.
superior vertical strain palpation
pts head is nodding inferiorly. superior strain is named for position of the base of the sphenoid. (simulate by sticking tongue out of mouth and toward chin).
Inferior vertical strain
sphenoid in extension, occiput in flexion. occurs as a result of downward blow anterior to SBS or upward blow posterior to SBS. (simulate by sticking tongue out of mouth and up toward nose).
occurs as the result of a direct lateral blow.
- two vertical axes: one through foramen magnum and one through body of sphenoid.
- bones rotate in the same direction around their axes.
Right lateral strain
lateral strain = "Parallelogram head" -- wings of sphenoid move to the left while body of the sphenoid moves right.
- body of occiput moves to the left as the squama of the occiput moves to the right.
Right lateral strain palpation
- pt sticks tongue out of mouth and around left ear.
non-physiologic strain patterrn named for relationship of the body of the sphenoid to the base of the occiput. compressed together. No axis of motion.
SBS compression palpation
- general lack of motion in both phases
- decreased CRI amplitude
SBS compression etiology
occurs as a result of the sphenoid and occiput being pushed together. blow to the forehead with force directed posteriorly and slightly inferiorly.