Cranial Midline Bones Flashcards
Midline/unpaired bones
Cranial - ethmoid, occiput, sphenoid
Facial - mandible, vomer
Motion of the midline bones
Usually rotate about TRANSVERSE axis in SAGGITAL plane, in ANTERIOR-POSTERIOR direction.
Paired bones
Cranial - parietal, temporal
Facial - inf nasal concha, lacrimal, maxilla, nasal. palantine, zygoma
Motion of paired bones
Usually around the AP axis in lateral motion (CORONAL PLANE) in EXTERNAL/INTERNAL ROTATION
Motion of SBS
Inhalation-flexion:
- sphenoid rotation, axis, direction
-occiput rotation, axis, direction
Sphenoid:
TRANSVERSE axis
Alae move ANTERIORLY
SBS motion is SUPERIOR
Occiput:
TRANSVERSE axis
Occiput move Posterior
SBS motion is SUPERIOR
SBS motion Cranial Flexion
SBS moves SUPERIOR Occiput - inf/post Sphenoid - ant/inf Ethmoid - same as occiput Palantine - ER Interpalantine suture - inf with vomer and maxillae
Ethmoid mirrors what bone’s motion?
Occiput
Vomer same as what bone’s motion?
Sphenoid
SBS and sacral motion - about what axis, in what plane and at what sacral segment
Transverse axis, thru 2nd sacral segment, in sagital plane
Sacral base moves in what direction in cranial flexion?
Also called what?
Sacral base posterior, apex anterior
Counterutation
Sacral base moves in what direction in cranial extension?
Sacral base moves anterior, apex posterior
Nutation
Ethmoid motion when SBS is in flexion is influenced by what?
sphenoid and falx cerebri
Lateral mass (ethmoid) motion during cranial flexion? Cranial extension?
Cranial flexion - external rotation
Cranial extension - internal rotation
SBS lateral strain - named for what?
Axis
*Sphenoid and occiput move in same or opposite direction?
Named for position of basi-sphenoid relative to basi-occiput
Two vertical axes.
Same direction
Basi-sphenoid shears right around vertical axis, occiput and sphenoid both rotate to the left around their vertical axes.
What is this strain pattern?
Right lateral strain
SBS vertical strain - named for what?
Axis
Plane of motion
*Sphenoid and occiput move in what direction?
Position of basi-SPHENOID(sup or inf)
Transverse axis
Motion in sagittal plane
Sphenoid and occiput move in opposite directions (one into extension, one into flexion)
Posterior direction = what vertical strain pattern?
Occiput into what position?
Sphenoid into what position?
inferior vertical strain
Occiput into flexion
Sphenoid into extension
Sphenoid extension, occiput flexion “thumbs point to doc”
Inferior vertical strain
SBS torsion - named for what?
Axis
Plane of motion
*Sphenoid and occiput move in what direction?
Named for more CEPHALAD greater wing of sphenoid
CORONAL PLANE
Sphenoid and occiput move in opposite directions
Abormal felxion/extension while sphenoid twists R (greater wing elevates on L), occiput twists L at SBS, L basi-sphenoid; “hands twist on each other with left thumb pointing to doc and right thumb moving away.
*What strain pattern is this?
left torsion
SBS torsion - relative change of other bones
- temporal and parietal
- mandible
- orbit
- membranes
temporal and parietal - ER on side of torsion
mandible - shifted toward side of torsion
orbit - smaller on side of torsion
membranes - falx (ant end rotates wtih sphenoid, post end rotates with occiput), tentorium (SB in same direction the occiput rotates), spinal dura (inf on side of low occiput)
SBS SB and Rotation - named for what? SB and Rotation: Axis Plane of motion *Sphenoid and occiput move in what direction?
Named for the CONVEXITY (wider side)
SB: 2 VERTICAL axes in the TRANSVERSE plane.
SB - sph and occ move in opposite directions
Rotation: 1 AP axis (like torsion) in CORONAL plane
Rot - sph and occ move in same direction
Side bending and rotation - rotation occurs to side of what? In what direction?
convexity
inferior or caudad
Sphenoid rotated L, SB R and occiput rotated R, SB R
Right SB rotation
SBS SB and Rotation - changes in other bones and membreanes
- temporal and parietal
- mandible
- orbit
- membranes
- temporal and parietal - externally rotated on convex
- mandible - shifted to convex side
- orbit - anterior on convex side
- membranes - falx (SB follows convexity of SBS of SBS), tentorium (follows occipital motion), spinal dura (inf on convexity)
Compression of SBS describe:
Due to, cranium feels like
due to trauma or pressure to head (i.e. infant cranium at birth)
Cranium feel rigid
Flexion of SBS
elevation of Sphenobasilar junction. All midline bones rotate around transverse axis. All paired lateral bones move into external rotation.
