The Skull Flashcards
How is skull type determined?
1) the angle of the petrous ridges to the MSP
2) the cephalic index
What are the three skull types?
1) mesocephalic
2) Dolichocephalic
3) Brachycephalic
What is the angle of the petrous ridges to the MSP for a mesocephalic skull?
47 degrees (average)
What is the angle of the petrous ridges to the MSP for a Brachycephalic skull?
54 degrees (wide skull)
What is the angle of the petrous ridges to the MSP in a Dolichocephalic skull?
40 degrees (long skull)
How do you calculate the cephalic index?
Width (parietal eminences) / length (frontal eminence to inion) X 100
What is the cephalic index for a mesocephalic skull?
75 - 80
What is the cephalic index for a Dolichocephalic skull?
Less then 75
What is the cephalic index for a brachycephalic skull?
More then 80
What is the parietal eminence?
The widest part of the skull
What is the landmark for the top of the petrous ridges?
TEA (top of ear attachment)
What line is used to line up the mandible and the frontal bone in an SMV projection?
The glabelloalveolar line (GAL)
What is the difference in angle between the OML (orbitomeatal line) and the IOML (infraorbitomeatal line) ?
7 degrees
What is the difference in angle between the OML (orbitomeatal line) and the GML (glabellomeatal line)
8 degrees
What is the difference in angle between the GML (glabellomeatal line) and the IOML (infraorbitomeatal line)?
15 degrees
Why is a PA projection of the skull typically preferred?
To help shield the eyes
What might you have to do when positioning an asthenic or hyposthenic patient in a lateral projection of the skull on the table?
Build up their chest
What might you have to do when positioning a hypersthenic patient for a lateral projection of the skull on the table?
Build up/ support their head
What might happen if we expose a patient while they have a ponytail in?
Their may be a circular artifact in the image
What does the patient need to remove for head imaging?
Jewelry, dental appliances, piercings, glasses, metal hair clips and they may need to take down their hair
Jewelry, dental appliances, piercings, glasses, metal hair clips and they may need to take down their hair
