Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
CHAPTER 11 SKULL & CRANIAL BONES SKULL • Divided into 2 regions 1. Cranium (8 bones) 2. Facial Bones (14 bones) 2 Regions of Cranium • Calvarium 1. Frontal 2. Right Parietal 3. Left Parietal 4. Occipital • Floor 1. Ethmoid 2. Sphenoid 3. Right Temporal 4. Left Temporal FRONTAL BONE • • • • Divided into 2 aspects: - squamous (or vertical portion) - orbital (or horizontal portion) Landmarks associated with Frontal Bone - Glabella - Superciliary ridge (arch) - Supraorbital margin (SOM) - Supraorbital groove - Frontal tuberosity (eminence) Articulations - Right Parietal Bone - Left Parietal Bone - Sphenoid - Ethmoid NOTE: The frontal bone articulates with 8 facial bones to be identified later. Parietal Bones • Right & Left Parietal Bones - make up the majority of the lateral walls of the cranium • Articulations - Frontal - Occipital - Temporal - The opposite parietal Occipital Bone • Inferoposterior aspect of calvarium • Squamous portion • External Occipital protuberance (inion) • Articulations - R & L Parietals - R & L Temporal - Sphenoid - Atlas (1st Cervical) Temporal Bone • Temporal Bones are paired structures. • R & L Temporal Bone - Houses the organs of hearing and balance • Significant parts: - zygomatic process - temporomandibular fossa - external acoustic meatus (EAM) -Mastoid process - Temporal styloid process Temporal Bone (continued) • Consists of 3 main parts 1. squamous 2. mastoid 3. petrous portions • Petrous ridge corresponds to the level of the TEA • Articulations - parietal - occipital - sphenoid - and two facials to be discussed later Sphenoid Bone • Body • Wings • 4 major parts 1. lesser wing 2. greater wing 3. sella turcica 4. clivis • Articulations - all seven cranial bones - and five facial bones Sella Turcica • Anterior Clinoid Process • Posterior Clinoid Process • Dorsum Sellae • Best seen in a true lateral. Ethmoid Bone • Crita galli • Cribriform plate • Lateral labyrinths (masses) • Perpendicular plate • Superior and middle nasal conchae Cranial Sutures • • • • • • • • • Lambdoidal Squamosal Coronal Sagittal Junction between sutures Bregma Lambda Pterions asterions Joint Classification Synarthroidal • • • • Infant Cranial Sutures & fontanels Anterior fontanel R & L Sphenoid fontanel R & L mastoid fontanel Posterior fontanel Skull Morphology • 3 skull classifications 1. brachycephalic 2. mesocephalic (average-shaped) 3. dolicephalic Cranial Topography • • • Facial Landmarks - Acanthion - Glabella - Gonion - IOM - Mental Point - Midlateral orbital margin - Nasion - Outer and inner canthus - SOG - Supercilliary ridge (arch) Body Planes - MSP - Interpubillary Line (IPL) Landmarks of the Ear - Auricle or pinna - EAM - TEA -Tragus • Skull Positioning Lines - AML (acantiomeatal line) - EAM (external acoustic meatus) - GAL (glabelloalveolar line) - GML (glabellomeatal line) - IOML (infraorbitomeatal line) - LML (lips meatal line) - MML (mentomeatal line) - OML (orbitomeatal line) • No Abbreviations (students must spell out each abbreviation to receive credit) Positioning and Technical Considerations • • • • • • Erect vs recumbent Medium kVp 75-85 Small focal spot (if equipment allows) AEC – center ionization cell Short exposure time Shielding Skull Series • Basic Projections - AP axial (Towne) - Lateral - PA 0 degree - PA 15 degree (caldwell method) • Special Projections - PA axial (Haas) - SMV (submentovertex) • Sella Turcica - Lateral - AP axial (Towne)