Lecture 4: Midline bones Flashcards
What are the midline/UNpaired bones?
- Cranial bones: occiput and sphenoid
- Facial bones:
- mandible
- vomer
- ethmoid
- frontal
How do midline bones move?
Flexion and extension
- Rotate about a transverse axis, in an anterior-posterior direction.
How do paired bones move?
-
IR/ER
- Move about a AP axis, in a lateral motion (coronal plane)
When the unpaired bones flex, the paired bones => ____________.
- Unpaired bones = flex
- Paired bones = ER
FLEXTERNAL ROTATION
When the unpaired bones extend, the paired bones => _______
- Unpaired bones = extend
- Paired bones = Internally rotate
PArts of the ethmoid bone
- Cribiform plate + crista galli
- Perpendicular plate
- Lateral masses (2)
In SBS flexion: sphenoid tips ________ => ethmoid bone tips ______ on ____ axis
Other changes?
SBS flexion = ethmoid flexes
-
Sphenoid tips anteriorly => ethmoid bone (perpendicular plate) (flexes) on transverse axis
- => crista galli swings superior and posterior
- => lateral masses ER (down and out) bc attached to cribiform plate and use as hinge d/t pull of ER on maxilla = move as paired bones
In SBS extension: sphenoid tips ________ => ethmoid bone tips ______ on ____ axis
Other changes?
SBS extension = ethmoid extends
- Sphenoid tips posterior => ethmoid bone (perpendicular plate) (extends) on transverse axis in saggital plane.
- => crista galli swings inferior and anterior
- => lateral masses IR (down and out) bc attached to cribiform plate and use as hinge d/t pull of ER on maxilla = move as paired bones
- When sphenoid tips anteriorly (in flexion), the ethmoid tips ________
- When the ethmoid tips _______, the lateral masses of the ethmoid _______
- When the sphenoid tips posteriorly (in extension), the ethmoid tips ______
- When the ethmoid tips ______, the lateral masses of the ethmoid ______
- When sphenoid tips anteriorly (in flexion), the ethmoid tips posterior
- When the ethmoid tips posterior, the lateral masses of the ethmoid ER
- When the sphenoid tips posteriorly (in extension), the ethmoid tips anteriorly
- When the ethmoid tips anteriorly, the lateral masses of the ethmoid IR
Ethmoid mirrors what bone’s motion?
Occiput
Vomer same as what bone’s motion?
Sphenoid
What drives the vomer?
Sphenoid bone
When sphenoid moves into flexion => vomer moves into flexion.
What bones does the vomer articulate with?
- sphenoid
- ethmoid
- septal
- cartilage
- maxillae
- palantines
What is the function of the vomer with SBS flexion?
-
Depresses the hard palate with SBS flexion.
- In flexion => creates a wider flat palate
- In extension => creates a narrower flat palate
- Posterior part: depresses the palatines, flattening the roof of the mouth
- Anterior part: ascends to allow premaxillae to ER.
When the SBS is in flexion,
the ethmoid will move in the same direction as the _____.
vomer will move in the same direction as the ____.
SBS flexion
- ethmoid = occiput
- vomer = sphenoid
vowels move together (e = o) = consenent move together (v = s)
What causes SD to the vomer?
SD to the vomer is usually due to the position of the sphenoid, caused by trauma to the face
How do you palpate the CRI?
Vault contact
- Index fingers rest on the greater sphenoid wings
- Middle fingers are usually anterior to the ear
- Ring fingers rest on the mastoid process
- Pinky fingers rest or reaches back to the occiput
- Palms may very lightly rest upon the parietals
- Thumbs may gently contact the frontal, hover above or rest contacting your own 2nd MCP
Palpatory findings with lateral strain
- 1st fingers move in opposite direction from pinky fingers
- Side of strain moves anteriorly
What palpatory findings do we see for a vertical strain?
SD due to: Injury superior/inferior in front of or behind the SBS
- Superior strain: “First fingers move away from doctor, and pinky fingers move to doctor”
- Inferior strain: “First fingers move TO doctor, and pinky fingers move AWAY from doctor”
what is the SD
Left sidebending rotation; name the SD for the side that is FULL (convexity developed in head)
What palpatory findings do you see with SB rotation?
- Named for the side that is fuller: 1st finger and pinky move away from each other
- Oppsite side shrinks: 1st finger and pinky move toward
In a R SB rotation, where was the site of impact located?
The actual contact causing the dysfunction is injury from a blow to the ear/ side of face on the LEFT (opposite side)
SBS Compression SD
due to?
- Occiput and sphenoid compress against one another in a AP- sagittal axis
- Due to trauma: whiplash/hit in front of head/ fall on back of head
- can mimic other patterns
Where is the injury in a lateral strain?
- Anterior or posterior (in front or behind) the SBS
- Trauma lateral to 1 side of anterior cranium or the opposite posteior cranium
Where is the injury in a vertical strain>?
supeiror or inferior
if you fall back and hit back of head, what sd will you get?
vertical strain: occiput moves up (superior) and sphenoid moves down (inferiorly)
if you hit top of head on cabinet door, what SD will you get
Vertical strain: occiput moves inferior and sphenoid moves superior
where is the injury in a torsion?
hit to side of face with a roll
where is the injury in SB rotation?
blow to ear /side of head
