1. Skull Radiography Cranium & Facial bones

2. Basic Projections Cranium PA / AP PA / AP PA15 0 PA15 0 Lateral Lateral Towne’s Towne’s Occipito-mental (OM) Occipito-mental (OM) Submento-vertical Submento-vertical Facial bones Occipito-mental (OM) Occipito-mental (OM) Occipito-mental (OM) 30 0 Occipito-mental (OM) 30 0 Towne’s Towne’s Submento-vertical Submento-vertical Views for mandible Views for mandible

4.  Interorbital or interpupillary line  Orbito-Meatal baseline (Radiographic baseline / baseline) – Line joining outer canthus of the eye to the central point of the EAM  Anthropomorphic baseline (anthropological baseline) / line of Frankfurt / Reid’s baseline – line joining infra-orbital margin to the upper border of the EAM

5. PA (Occipito-Frontal) Forehead and nose rests against bucky.Forehead and nose rests against bucky. EAMs are equidistant from the bucky.EAMs are equidistant from the bucky. Baseline and median sagittal plane are right angled to the bucky.Baseline and median sagittal plane are right angled to the bucky. Centre in midline at the level of EAM – perpendicular to the buckyCentre in midline at the level of EAM – perpendicular to the bucky

6. PA (Occipito-Frontal) Forehead and nose rests against bucky Forehead and nose rests against bucky EAMs are equidistant from the bucky EAMs are equidistant from the bucky Baseline and median sagittal plane are right angled to the bucky Baseline and median sagittal plane are right angled to the bucky Cassette ;- 24x30 cm lengthwise Cassette ;- 24x30 cm lengthwise Centre in midline at the level of EAM – perpendicular to the bucky Centre in midline at the level of EAM – perpendicular to the bucky 70 kV, 40 mAs, 100 cm 70 kV, 40 mAs, 100 cm

7. Radiographic Appearance - PA Criteria Entire cranial perimeter from vertex to the mastoid process and both lateral borders.Entire cranial perimeter from vertex to the mastoid process and both lateral borders. Equal distance from the lateral border of the skull to the lateral border of the orbit on both sides.Equal distance from the lateral border of the skull to the lateral border of the orbit on both sides. Symmetric petrous ridges lie at the level of upper border of the orbits.Symmetric petrous ridges lie at the level of upper border of the orbits.