Skull/SinusesFree
Skull baselines and routine skull projections
Know the baselines; the petrous ridges then show if the angle was right: filling the orbits or lower third.
The baselines
Skull positioning uses lines on the face. The orbitomeatal line, OML, runs from the outer canthus of the eye to the external acoustic meatus. The infraorbitomeatal line, IOML, runs from the infraorbital margin to the EAM, and it sits about 7 degrees from the OML. The glabelloalveolar line runs from the glabella to the alveolar process of the maxilla, and the mentomeatal line runs from the chin to the EAM. The interpupillary line connects the pupils and is used to check tilt.