Skull landmark

Basics of skull Lining and Landmark for Radiography.

1. Radiography of The Skull Goutam Suklabaidya Assistant PROFESSOR(RADIOLOGY) SHARDA UNIVERSITY

2. PARANASAL SINUSES The large, air-filled cavities of the paranasal sinuses are sometimes called the accessory nasal sinuses because they are lined with mucous membrane, which is continuous with the nasal cavity. These sinuses are divided into four groups, according to the bones that contain them

3. SINUSES The Sinuses are Divided into four group- 1.Maxillary 2. Frontal 3. Ethmoid 4. Sphenoid

4. Maxillary The large maxillary sinuses are paired structures, one of which is located within the body of each maxillary bone. Each maxillary sinus is shaped somewhat like a pyramid on a frontal view. Laterally, they appear more cubic

5. Frontal Sinuses The frontal sinuses are located between the inner and outer tables of the skull, posterior to the glabella The maxillary sinuses are always paired and the frontal sinuses are rarely symmetric. The frontal sinuses usually are separated by a septum.

6. Ethmoid Sinuses The ethmoid sinuses are contained within the lateral masses or labyrinths of the ethmoid bone. These air cells are grouped into anterior, middle, and posterior collections, but they all intercommunicate. When viewed from the side, the anterior ethmoid sinuses appear to fill the orbits. This occurs because portions of the ethmoid sinuses are contained in the lateral masses of the ethmoid bone, which helps to form the medial wall of each orbit.

7. Sphenoid Sinuses The sphenoid sinuses lie in the body of the sphenoid bone directly below the Sella turcica. The body of the sphenoid that contains these sinuses is cubic and frequently is divided by a thin septum to form two cavities. This septum may be incomplete or absent entirely.

8. Major Landmarks used for skull radiography 1. Vertex 2. External Occipital Protuberance (E.O.P.) 3. External Auditory Meatus (EAM) 4. Outer Canthus Of Eye. 5. Infra-orbital point 6. Nasion 7. Glabella

9. Major body planes used in Skull radiography The Median Sagittal plane. A vertical plane dividing the skull into 2 symmetrical right and left halves when viewed from the anterior aspect.

10. The Anthropological plane, This plane splits the skull into upper and lower halves passing along the anthropological baseline lines.

11. The Auricular plane This plane divides the skull into anterior and posterior compartments along the Auricular lines

12. Major Baselines used in Skull Radiography Anthropological Orbital Meat al Interpupillary The Auricular Line

13. Anthropological line The Anthropological line The Isometric “Baseline” which runs from the inferior orbital margin to the upper border of the external auditory meatus (EAM)

14. The Orbital-Meatal Line(OML) The original “Baseline” which runs from the Nasion through the outer canthus of the eye to the Centre of the external auditory meatus.

15. Interpupillary line The Interpupillary line The line connects the center's of the orbits and is at 90 degree to the median sagittal plane.

16. Auricular Line The Auricular Line This line passes at 90 degrees to the anthropological line through the Centre of the external auditory meatus. Note: there is a difference of 10 to 15 degrees between the Orbital-Meatal line and the anthropological line