Skull Anatomy PDF

Skull Anatomy  Skull is skeleton of head It is formed by articulation of 21 immovable bones and 1 movable bone “mandible”  21 immovable bones 8 paired bones 5 unpaired bones 1. Parietal bones 1. Frontal b...

Skull Anatomy  Skull is skeleton of head It is formed by articulation of 21 immovable bones and 1 movable bone “mandible”  21 immovable bones 8 paired bones 5 unpaired bones 1. Parietal bones 1. Frontal bone 2. Temporal bones 2. Sphenoid bone 3. Zygomatic bones 3. Ethmoid bone 4. Maxillary bones 4. Vomer 5. Nasal bones 5. Occipital bone 6. Lacrimal bones 7. Inferior concha 8. Palatine bones 8 paired bones Parietal bones Palatine bone Nasal bones Temporal bones Lacrimal bone Inferior concha Zygomatic bone Maxillary bone  5 unpaired bones Frontal bone Sphenoid bone Occipital bone Ethmoid bone Vomer  Bones of the Skull Cranium: upper and posterior part that encloses brain Facial Skeleton: Anterior part of skull divided into fixed upper part and lower movable part From front: Norma frontalis From back : Norma occipitalis From top: Norma verticalis From side: Norma lateralis From base: Norma basalis Norma Frontalis  Frontal eminence Formed of : [ 1frontal bone 2 maxillary 2 zygomatic 2 nasal  Norma Frontalis sutures Frontomaxillary Frontonasal Frontozygomatic Maxillary nasal Zygomaticomaxillary General Features: 1. Frontal eminence:Most prominent areas on either side of forehead 2. Superciliary arch:Above medial part of superior orbital margin 3. Glabella: Between 2 superciliary arches 4. Nasion:Meeting point between frontonasal and internasal sutures General Features: 1. Anterior nasal spine: Median projection of lower border of external nasal aperture 2. Canine eminence: Projection formed by root of canine tooth 3. Canine fossa: Shallow depression lateral to canine eminence 4. Incisive fossa: Shallow depression medial to canine eminence 5. Zygomatico facial foramen :in zygomatic bone 6. Infraorbital foramen :in maxillary bone 7. Supraorbital notch:in frontal bone  ORBITAL CAVITY A pyramidal space with a base, apex and four walls. Boundaries and Walls: Roof Orbital plate of frontal bone Floor Frontal 1.Orbital surface of maxilla bone 2.Zygomatic bone Medial wall Greater wing Lacrimal Ethmoid 1.Lacrimal bone of sphenoid bone bone 2.Orbital plate of ethmoid bone Maxillary Lateral wall bone 1.Zygomatic bone. 2.Greater wing of sphenoid bone.  Optic canal Lacrimal fossa Trochlear fossa Roof: Bony Orbit: Floor: Inferior orbital Infraorbital groove Fissure Lateral Wall: Medial Wall: Ant & Post. Ethmoidal foramina Superior orbital Fissure Lacrimal groove Inferior orbital Fissure Norma Verticalis Formed of: Anterioly: Frontal bone Sides:2 parietal bones Posteriorly: Occipital bone General Features: Cornonal suture: between frontal and parietal bones Sagittal sutures: between 2 parietal bones Lamboid suture: between occipital and parietal bones General Features: N.B: Metpic suture only in fetal skull separating between 2 frontal bones,it disappears by 6 years Bregma: meeting point between coronal and sagittal sutures.(It is site of anterior /bregmatic fontanelle which closes during 2nd year (18 months) Lamda:meeting point between sagittal and lamboid suture(It is posterior fontanelle that closes during 1st year General Features: Parietal emienence: most convex part f parietal bone Parietal emissary foramen: on each side of sagittal suture ,3.5 cm anterior to lamboid suture The mandible The mandible Symphysis menti The mandible Ramus Alveolar part Body Base  Body of the mandible Inner surface It has two surfaces It has two borders Outer surface  Body of the mandible Lateral aspect (Outer surface) Oblique line Mental Protuberance Premolars Molars Mental foramen Mental symphysis Mental Tubercles Angle of the mandible  Body of the mandible Medial aspect Mandibular foramen (Internal surface) Lingula Mylohoid groove Mylohoid line Genial tubercle Sublingual fossa Submandibular fossa Digasteric fossa Ramus of the mandible Condylar head Pterygoid fovea Coronoid process Condylar neck Mandibular notch  Frontal bone Ethmoid bone (sinus) Orbit Zygomatic bone Maxillary bone (sinus) On the provided skull identify the following: - Frontal, parietal, temporal, occipital, maxillary and zygomatic bones. - Sagittal, coronal, lambdoid sutures. - Glabella, nasion, pterion & asterion. - Temporal fossa & infra temporal fossa. - External occipital protuberance & crest. - Inferior, superior nuchal lines. - Mastoid and styloid processes. - Mandible (body, ramus, head, neck, mandibular foramen) - Walls of orbital cavity. - Nasal cavity. 35