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Flashcards in OCMM Cranial - Midline Bones Deck (16)
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1

Describe flexion of the ethmoid

Perpendicular plate is rotated by the sphenoid about its transverse axis — this swings the crista galli superiorly and posteriorly

There may be accompanying external rotation — lateral masses expand inferiorly (using attachments to cribriform plate as a hinge) d/t pull of external rotation of the maxillae

2

Describe extension of the ethmoid

Perpendicular plate is rotated by the sphenoid about its transverse axis — this swings the crista galli inferiorly and anteriorly

May be accompanied by internal rotation d/t internal rotation of maxillae with SBS extension

3

Clinical considerations with ethmoid SD

Sinusitis (ethmoid bone has pumping action on ethmoid sinus)

Septal deviation (ethmoid spine allows some lateral deviation)

Headache (d/t lymphatic drainage through cribriform plate; increased dural tension or vascular effects may lead to tension HA or migraine symptomatology)

4

Axes associated with SBS vertical strain

2 transverse axes

With superior vertical strain, bones rotate anteriorly around involved axis; with inferior vertical strain, bones rotate posteriorly around involved axis

5

With a superior vertical strain, the sphenoid is considered _____ while the occiput is considered _____

Flexed; extended

The sphenoid is flexed with rotation around its transverse axis and basisphenoid superior; bilateral anterior quadrants are in external rotation

The occiput is extended with rotation around its tranverse axis; bilateral posterior quadrants are in internal rotation

[opposite is true with inferior vertical strain]

6

Axes associated with SBS torsion

Sphenoid and occiput rotate in opposite directions around an AP (sagittal) axis

The side with the higher greater wing = anterior quadrant is in relative external rotation

The side with the lower greater wing =anterior quadrant is in relative internal rotation

[Dr. Danto note — “For torsions, think of the sphenoid on the high-wing side as being in extension and the Occiput on that side being in flexion...and vice versa on the opposite side. However, due to the wonderful mechanics of the human body, the Occiput drives all of the paired bones into External Rotation when it is in flexion. So that is why all the facial features essentially match those found in ER despite the sphenoid being in extension (usually matched with IR)”]

7

Axes associated with SBS lateral strain

2 vertical axes (superior/inferior) — go through foramen magnum and body of the sphenoid

8

Which of the cranial strain patterns is referred to as a “parallelogram head”?

SBS lateral strain

9

Axes associated with sidebending rotation dysfunction

1 sagittal (AP) axis from opisthion to nasion = rotation; sphenoid and occiput spin in same direction

2 vertical axes: FM and body of sphenoid = sidebending; sphenoid and occiput spin in opposite directions

Note: the side of the lower greater wing and occiput is in relative flexion; high side is in relative extension [named side feels fuller]

10

Vault contact palpation technique to test for SBS compression

Lift lateral angles of frontal bone anteriorly with thumbs while stabilizing the lateral angles of the occiput posteriorly with the hands — focus attention on SBS

11

Findings in SBS flexion SD in terms of restricted motion, head diameter, forehead, eyes, paired bones, ears

Restricted motion = extension

Head diameter increased in transverse dimension

Forehead wide and sloping

Eyes prominent

Paired bones externally rotated

Ears protruding

12

Findings in SBS extension SD in terms of restricted motion, head diameter, forehead, eyes, paired bones, ears

Restricted motion = flexion

Head diameter increased in longitudinal dimension

Forehead vertical

Eyes receded

Paired bones IR

Ears close to head

13

Findings in SBS torsion in terms of the following on the side of the HIGH sphenoid wing:

Frontal lateral angle
Orbit
Frontozygomatic angle
Eyeball
Zygomatic orbital rim
Symphysis menti
Mastoid tip
Ear

Frontal lateral angle anterior
Orbit wide
Frontozygomatic angle increased
Eyeball protruded
Zygomatic orbital rim everted and ER
Symphysis menti toward high side
Mastoid tip posteromedial
Ear protruding

14

Findings in SBS torsion in terms of the following on the side of the LOW sphenoid wing:

Frontal lateral angle
Orbit
Frontozygomatic angle
Eyeball
Zygomatic orbital rim
Symphysis menti
Mastoid tip
Ear

Frontal lateral angle posterior
Orbit narrow
Frontozygomatic angle lessened
Eyeball retruded
Zygomatic orbital rim inverted and IR
Symphysis menti away from low side
Mastoid tip anterolateral
Ear close to head

15

Findings in SBS sidebending and rotation on side of concavity:

Frontal lateral angle
Orbit
Frontozygomatic angle
Eyeball
Zygomatic orbital rim
Symphysis menti
Mastoid tip
Ear

Frontal lateral angle posterior
Orbit narrow
Frontozygomatic angle lessened
Eyeball retruded
Zygomatic orbital rim prominent
Symphysis menti towards concavity
Mastoid tip posteromedial
Ear protruding


[note side of concavity is in extension/IR]

16

Findings in SBS sidebending and rotation on side of convexity:

Frontal lateral angle
Orbit
Frontozygomatic angle
Eyeball
Zygomatic orbital rim
Symphysis menti
Mastoid tip
Ear

Frontal lateral angle anterior
Orbit wide
Frontozygomatic angle increased
Eyeball protruded
Zygomatic orbital rim flat
Symphysis menti away from convexity
Mastoid tip anterolateral
Ear close to head


[note side of convexity is in flexion/ER]