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Rad Pro Ch.11 Part 2
Cranium "Skull"
| Question | Answer |
|---|---|
| How many cranial bones are there? | 8. |
| Frontal Bone | This bone contributes to the formation of the forehead and the superior part of each orbit. |
| Squamous or Vertical Portion | -Glabella. -Supraorbital Groove (SOG). |
| Glabella | Is the smooth raised prominence between the eyebrows just above the bridge of the nose. |
| Supraorbital Groove (SOG) | Is the slight depression above each eyebrow. |
| Supraorbital Margin (SOM) | The superior rim of each orbit |
| Supraorbital Notch (Foramen) | Is a small hole or opening within the SOM slightly medial to its midpoint |
| Orbital or Horizontal Portion | -SOMs. -Superciliary Ridges. -Glabella. -Frontal Tuberosities. |
| Orbital Plate | On each side forms the superior part of each orbit. |
| Ethmoidal Notch | Separates each orbital plate. |
| The frontal bone articulates with ______ cranial bones: | 4; right & left parietals, sphenoid, and ethmoid. |
| Parietal Tubercles (Eminences) | The widest portion of the entire skull is located here of the two parietal bones. |
| Occipital Bone | The inferoposterior portion of the calvarium. |
| Squamous Portion | The external surface of the occipital bone presents a rounded part. |
| The occipital bone articulates with _______ bones: | 6; 2 parietals, 2 temporals, sphenoid, and atlas. |
| External Occipital Protuberance or Inion | Is the prominent bump or protuberance at the inferoposterior portion of the skull. |
| Foramen Magnum | The large opening at the base of the occipital bone through with the spinal cord passes as it leaves the brain. "Great Hole". |
| Condylar Portions (Occipital Condyles) | Are oval processes with convex surfaces, with one on each side of the foramen magnum. |
| Atlanto-Occipital Joint | The two-part articulation between the skull and the cervical spine. |
| Right & Left Temporal Bones | Are complex structures that house delicate organs of hearing and balance. |
| Zygomatic Process | Extending anteriorly from the squamous portion of the temporal bone. |
| Zygomatic Arch | The zygomatic process meets the temporal process of the zygomatic bone to form the easily palpated _____________________. |
| Temporomandibular (TM) Fossa | Into which the mandible fits to form the TMJ. |
| Each temporal bone is divided into _____ primary parts? | 3; squamous, mastoid portion, petrous portion. |
| Squamous Portion | Is the thin upper portion that forms part of the wall of the skull. |
| Mastoid Portion | Area posterior to the EAM with a prominent mastoid process or tip. |
| Petrous Portion | Dense; also called the petrous pyramid or pars petrosa; it houses the organs of hearing equilibrium. |
| Petrous Ridge or Petrus Apex | The upper border or ridge of the petrous pyramid. |
| The petrous ridge of these pyramids corresponds to the level of an important external landmark: | TEA (top of the ear attachment). |
| Internal Acoustic Meatus | Is an opening or orifice which serves to transmit nerves of hearing equilibrium. |
| Each temporal bone articulates with ____ cranial bones: | 3; parietal, occipital, and sphenoid. |
| Sphenoid Bone | Forms the anchor for the other 7 cranial bones. |
| Sella Turcica | The central depression on the body; looks like a saddle from the side. |
| Hypophysys Cerebri or Pituitary Gland | Surrounded and protected by the sella turcica. |
| Dorsum Sellae | Posterior to the sella turcica and is best seen laterally. |
| Clivus | Is a shallow depression that begins on the posteroinferior aspect of the dorm sellae of the sphenoid bone and extends posteriorly to the foramen magnum at the base of the occipital bone. |
| Lesser wings | Smaller pair; are triangular and are nearly horizontal. |
| Anterior Clinoid Process | Project laterally from the superoanterior portion of the body and extend to about the middle of each orbit. |
| Greater Wings | Extend laterally from the sides of the body and form a portion of the floor of the cranium and a portion of the sides of the cranium. |
| Foramen Rotundum & Foramen Ovale | Are seen as small opening on superior and oblique views. |
| Superior Orbital Fissures | These opening provide additional communication with the orbits for numerous cranial nerves and blood vessels. |
| Pterygoid Process or Plates | Form part of the lateral walls of the nasal cavities. |
| The sphenoid articulates with all ______ other cranial bones. | 7. |
| The sphenoid also articulates with _____ facial bones. | 5. |
| Ethmoid Bone | Lies primarily below the floor of the cranium. |
| Cribriform Plate | Small horizontal portion; contains many small openings or foramina through which segmental branches of the olfactory nerves pass. |
| Crista Galli | Projecting superiorly form the cribriform plate; which is derived from "rooster's comb". |
| Perpendicular Plate | Projecting downward is the midline; which helps form the bony nasal septum. |
| Superior & Middle Nasal Conchae or Turbinates | Extending medially and downward fromm the medial wall of each labyrinths are thin scroll-shaped projections of bone. |
| Lateral Labytinths (masses) | Are suspended from the undersurface of the cribriform plate on each side of the perpendicular plate; help to form the medial walls of the orbits and lateral walls of the nasal cavity. |
| The ethmoid articulates with _____ facial bones: | 11. |
| The ethmoid articulates with _____ cranial bones: | 2; frontal & sphenoid. |
| Sutures | Articulations or joints of the cranium and are classified as fibrous joints. |
| Coronal Suture | Separates the frontal bone from the 2 parietal bones. |
| Sagital Suture | Separates the 2 parietal bones in the midline. |
| Lambdoidal Suture | Separates the 2 parietal bones from the occipital bone. |
| Squamosal Sutures | Are formed by the inferior junction of the 2 parietal bones with their respective temporal bones. |
| Bregma | The anterior end of the sagittal suture. |
| Lambda | The posterior end. |
| Asterions | Left and right; are posterior to the ear where the squamosal and lambdoidal sutures meet. |
| Pterions | Left and right; are points at the junction of the frontal, parietals, temporals, and the greater wings of the sphenoid. |
| Infant Cranium & Fontanels | Membrane covered; Have 6 Fontanels: -Anterior fontanel. -Posterior fontanel. -Left sphenoid fontanel. -Right sphenoid fontanel. -Left mastoid fontanel. -Right mastoid fontanel. |
| AP Axial: Towne Method | - CR 30° to OML or 37° IOML. - CR 2.5" above glabella. |
| Lateral Skull | - MSP parallel. - Interpupillary perpendicular. - CR 2" superior to EAM. |
| PA Axial: Caldwell Method | - CR 15° caudad. - Petrous ridges over lower ⅓ of orbits. |
| PA Projection | - CR 0° PA. - Petrous ridges over supraorbital margin. |
| Alternative PA Axial | - CR 25°-30° caudad . - Petrous pyramids are projected at or just below the IOM to allow visualization of the entire orbital margin. |
| Trauma AP | - CR parallel to OML. - CR to glabella. |
| SMV Projection | - CR perpendicular to IOML and IR. - CR 1½" inferior to mandibular symphysis. |
| PA Axial: Haas Method | - OML perpendicular. - CR 25° cephalad. - CR exit 1½ in (4 cm) superior to nasion. * Dorsum sellae appears larger within foramen magnum. * Magnification of occipital bone evident. |
| EAM (External Acoustic Meatus) | Is the opening of the external ear canal. |
| GML (Glabellomeatal Line) | A line that is located between the global and the EAM. |
| OML (Orbitomeatal Line) | Is a frequently used positioning line that is located between the outer cants and EAM. |
| IOML (Infraorbitomeatal Line) or (Reid's Base Line) | Is formed by connecting the IOM to the EAM. |
| There is __________ difference b/w the OML & IOML. | 7°-8°. |
| AML (Acanthiomeatal Line) | Connects the acanthion to the EAM. |
| MML (Mentomeatal Line) | Connects the mental point to the EAM. |
| LML (Lips-Meatal Line) | A line of junction of the lips to the EAM. |
| GAL (glabelloalveolar Line) | Connects the glabella to a point at the anterior aspect of the alveolar process of the maxilla. |
| IPI (Interpupillary or Interorbital Line) | Is a line that connects the pupils or the outer canthi of the patient's eye. |
| Inion | Is the most prominent point of the external occipital protuberance. |
| Mesocephalic | 47°. |
| Brachycephalic | 54°. |
| Dolicephalic | 40°. |