SHANDONG UNIVERSITY Liu Zhiyu Skull SHANDONG UNIVERSITY Liu Zhiyu
Skull The skull is composed of 23 bones, which may be divided into the cerebral craniumand facial cranium
Skull Cerebral cranium (8) ―larger, upper and posterior part, contains and protects the brain Single bones: include frontal bone ethmoid bone sphenoid bone occipital bone Paired bones: include temporal bone parietal bone
Skull Bones of facial cranium (15) ―smaller, lower, and anterior part, contains bones that surrounded the eye, nose and mouth Single bones: include mandible vomer hyoid bone Paired bones: include maxilla nasal bone lacrimal bone palatine bone zygomatic bone inferior nasal concha
Bones of facial cranium
parietal bone Frontal bone Sphenoid bone Temporal bone Zygomatic bone Occipital bone Nasal bone Maxilla Mandible
Mandible Body of mandible Superior border: alveolar arch Inferior border: base of mandible Outer surface: mental protuberance Mental foramen Inner surface: mental spine Digastric fossa
Mandible Ramus Mandibular notch Coronoid process Condylar process head of mandible neck of mandible Mandibular foramen Mandibular lingula Angle of mandible Masseteric tuberocity
The skull as a whole
Skull viewed from above (superior view) Bones: frontal bone paired parietal bone occipital bone Sutures: Coronal suture Sagittal suture Lambdoid suture parietal tuber parietal foramen
Skull viewed from above (superior view) Internal surface of the calvaria sulcus for superior sagittal sinus granular foveola arterial grooves
Skull viewed from behind External occipital protuberance Superior nuchal line Inferior nuchal line
Internal view of base of skull Base of skull forms three fossae Anterior cranial fossa Middle cranial fossa Posterior cranial fossa
Internal view of base of skull
Anterior cranial fossa Formed by orbital part of frontal bone, cribriform plate of ethmoid, and lesser wings of sphenoid Structures: frontal crest foramen cecum crista galli cribriform plate cribriform foramina
Meddle cranial fossa Structures: Formed by the body and greater wings of sphenoid, petrous part of temporal Structures: Body of sphenoid bone Hypophysial fossa Optic canal Anterior clinoid process Tuberculum sellae Dorsum sellae Posterior clinoid process Sella turcica
Meddle cranial fossa Carotid sulcus Superior orbital fissure Foramen rotundum Foramen ovale Foramen spinosum Sulcus for middle meningeal artery Foramen lacerum Internal opening of carotid canal Trigeminal impression Arcuate eminence Tegmen tympani
Posterior cranial fossa Formed by occipital and the petrous part of temporal Structures: foramen magnum clivus internal opening of hypoglossal canal internal occipital protuberance internal occipital crest sulcus for transverse sinus sulcus for sigmoid sinus jugular foramen internal acoustic pore internal acoustic meatus
Skull viewed from below (inferior view) alveolar arch bony palate median palatine suture incisive foramina incisive canal greater palatine foramen posterior nasal apertures pterygoid process occipital condyle external opening of hypoglossal canal external opening of carotid canal styloid process stylomastoid foramen mandibular fossa articular tubercle
Lateral view of the skull External acoustic pore Mastoid process Zygomatic arch Temporal fossa Pterion Superior temporal line
Lateral view of the skull Infratemporal fossa pterygomaxillary fissure pterygopalatine fossa sphenopalatine foramen
Skull viewed from the front (anterior view) Frontal region: frontal squama frontal tuber superciliary arch glabella
Orbit Base: supraorbital notch infraorbital foramen Apex: optic canal pyramid-shaped paired cavities Base: supraorbital notch infraorbital foramen Apex: optic canal Walls Superior: fossa for lacrimal gland Medial: fossa for lacrimal sac Inferior: infraorbital fissure infraorbital groove infraorbital canal
Bony nasal cavity Roof: cribriform plate of ethmoid Floor: bony palate Medial wall ― bony septum of nose Lateral wall Superior, middle and inferior nasal conchae Superior, middle and inferior nasal meatus (underlying each concha) Sphenoethmoidal recess above superior nasal concha Anterior ―piriform aperture Posterior ―posterior nasal aperture communicates with pharynx
Paranasal sinuses Frontal sinus Lies in frontal bone, deep to superciliary arch Drain to anterior part of middle meatus
Paranasal sinuses Maxillary sinus Largest paired sinus, lie in the body of maxilla; Opening into middle nasal meatus
Paranasal sinuses Ethmoidal cellules Lie in ethmoidal bone, contains large number of air cells, divided into anterior, middle and posterior groups Anterior and middle groups drain into middle nasal meatus, while posterior group drains into superior nasal meatus
Paranasal sinuses Sphenoidal sinus Lies in body of sphenoid bone Drain into sphenoethmoidal recess
General characters of the skull at birth The skull at birth is large in proportion to rest of the skeleton ―1/4 (adult 1/7) The facial portion equals about one eight that of the cranium in size, whereas in adult it is one half (1/4) Many bones consist of more than one piece
General characters of neonatal skull Cranial frontanelles ―unossified membrane between the bones at the angles of parietal Anterior frontanelle ―closes during middle of 2nd year Posterior frontanelle ―closes by the end of 2nd month after birth Mastoid fontanelle Sphenoidal fontanelle
Anteroposterior radiograph of skull.
Lateral radiograph of skull.
Horizontal CT at level of upper part of ramus of mandible showing relationships of the pterygoid plates.