Axis and Motion of Cranial Bones Flashcards
What are the Midline/Unpaired bones?
Occiput
Sphenoid
Mandible
Vomer
Ethmoid
What are the Pair Bones?
Frontal
Parietal
Temporal
Inferior nasal concha
Lacrimal
Maxilla
Nasal
Palatine
Zygoma
General Motion of Midline Bones
Flexion and Extension
General Motion of Paired Bones
Internal and External Rotation
Movement of Ethmoid during SBS Flexion
Rotated by the sphenoid
Bottom of perpendicular plate goes inferior
The crista galli swings superior and posterior
Lateral masses externally rotate
Movement of Ethmoid during SBS Extension
Crista galli rotates anterior and inferior
Perpendicular plate rotates posterior and superiod
Lateral masses internally rotate
Movement of Vomer during SBS Flexion
Widens Palate
Posterior part goes superior
Anterior part goes inferior
Movement of Vomer during SBS Extension
Narrow tall palate
Posterior part of vomer moves inferiorly
Anterior part of the vomer moves superiorly
How do the ethmoid and vomer move in relation to the occiput and sphenoid?
Ethmoid and occiput move together
Vomer and sphenoid move together
Clinical Correlation of the Vomer
SD of the vomer usually secondary to the position of the sphenoid
Usually from facial trauma
Movement of Occiput and Sphenoid in SBS Flexion
Sphenoid rotates anteriorly
Occiput rotates posteriorly
Making cranial “bowl” bigger
Movement of Occiput and Sphenoid in SBS Extension
Sphenoid rotates posteriorly
Occiput rotates anteriorly
Making cranial “bowl” smaller
What axis does the vomer and ethmiod rotate around
Transverse axis
What axis of motion do the Parietal bones rotate?
AP axis
When the SBS is in flexion how does the Parietal bone rotate?
External rotation
Causing cranium to wide
When the SBS goes into Extension, how does the Parietal bone move?
Internal rotation
Cranium narrows
Signs and Symptoms of Mechanical Parietal Bone Dysfunction
Cranial synostosis - Premature closure of sutures
Head pain - pain along sutures that radiates from point of restriction (usually to oxipitomastoid and asterion)
Tension headaches
Pterion involved in temporal headaches
Signs and Symptoms of Organ/Nerve Parietal Bone Dysfunction
Middle Meningeal A. (trauma or giant cell arteritis)
Head, face, and tooth pain - temporal muscle SD, parietosquamosal, or P-sphnoid
Sagittal Synostosis
Most common synostosis
Premature fusion of the sagittal suture
Causes elongation of the craium - kinda looks like a football
Lambdoid Synostosis
Commonly mistaken for posterior positional deformational plagiocephaly
Results in flattening on one side of the back of the head, ear on ipsilateral side is more posterior
Other half of head continues to grow - head looks like “banana”
Causes a “tilt” at cranial base
When SBS is in flexion how do the temporal bones move?
Externally rotates
Zygomatic process less prominent
Bottom moves interiorly
Top moves externally
Widens cranium
When SBS is in extension how do the temporal bones move?
Internal rotation
Zygomatic process more prominent
Bottom moves externally
Top moves internally
What axis does the temporal bone rotate around?
An Oblique axis located just inferior to the petrous ridge
Mechanical Signs and Symptoms of Temporal Bone SD
TMJ pain
Head pain - pain along suture
Neck pain - interdependent dysfunction with SCM and other muscles
