Bones and cavities of the facial cranium TMJ

Bones and cavities of the facial cranium

TMJ

Anterior Skull frontal bone supraorbit al foramen zygomatic bone mandibula r symphysis mental foramen glabella infraorbita l foramen maxillar y bone alveolar fossa mandible

Anterior Skull perpendicular plate superior orbital fissure inferior nasal concha bone nasal bone middle nasal concha vomer bone

Paranasal Sinuses frontal sinus ethmoid sinus maxilary sinus sphenoid sinus

coronal suture sagittal suture lambdoidal suture Cranium frontal bone parietal bon occipital bone

Ventral Skull palatine process palatine bone vomer bone temporal bone external occipital protuberance sphenoid bone styloid process mastoid proces occipital bone

carotid canal jugular foramen magnum Occipital bone occipital condyle

squamosal suture lacrimal bone temporal bone external acoustic meatus mandibular condyle In mandibular fossa Lateral Skull

zygomatic arc sphenoid bone sutural bone mastoid process styloid process Lateral Skull coronoi d process ramus angle body mandible

cribriborm plate crista galli lesser wing greater wing optic canal intenal acoustic meatus sella turcica ugular foramen jugular Internal Skull

Hyoid + external acoustic meatus Hyoid bone temmporal mandibular joint

________ Sagittal

Coronal Lambdoid Squamous

Overview of Skull Geography • Facial bones form the anterior aspect • The cranial bones enclose the brain

Vault • The cranial vault or calvaria forms the superior, lateral, and posterior aspects of skull • The cranial base forming the inferior aspect of skull

Cranial Base • Cranial base forms the skull’s inferior aspect • Three prominent ridges divide the base into fossae • The brain rests on these cranial fossae completely enclosed by the cranial vault • The brain occupies the cranial cavity

Cranium • The 8 cranial bones include; 2 parietal, 2 temporal frontal, occipital, sphenoid, ethmoid • Cranium is self- bracing allowing the bones to be thin, yet strong

Occipital bone • Forms most of the posterior wall and base of skull • Articulates with parietal & temporal • Joins w/ sphenoid in the cranial floor • Forms internal walls of posterior cranial fossa

Occipital bone - Int. landmarks • Hypoglossal canal, Posterior cranial fossa

Temporal Bone • Forms the inferolateral aspects of the skull • Parts of the cranial floor • Divided into four regions; squamous tympanic, mastoid, and petrous-(int)

Temporal Bone • The internal petrous region contributes to the cranial base • The petrous region and the sphenoid bone form the middle cranial fossa

Temporal Bone - landmarks • Zygomatic process – Meets the zygomatic bone – Forms the cheek • Mandibular fossa – Receives condyle of mandible

Temporal bones - landmarks • Stylomastoid foramen – exit for facial nerve • Carotid canal – entrance for the carotid artery which supplies blood to cerebral hemispheres

Sphenoid bone • Bone spanning the width of middle cranial fossa • Articulates as central wedge of all cranial bones • Consists of central body and three processes; greater and lesser wings and pterygoid process (pos. view)

Sphenoid - landmarks • • • Sella turcica (enclosure for pituitary gland) Optic foramina (passage of optic nerves) Superior orbital fissure (Nerves III, IV, V enter orbit) Foramen rotundum & ovale (Cranial Nerve V to face) Foramen spinosum (Middle meningeal artery)

Ethmoid bone • Forms most of the area between the nasal cavity & orbits of eyes • Lies between nasal bones & sphenoid • Complex shape gives rise to nasal septum, sinuses and cribiform plate

Ethmoid bone - landmarks • Cribiform plates – Forms roof of nasal cavity • Olfactory formina – Olfactory nerves enter brain • Crista galli – Attachment of the dura mater which secures brain in cavity

Facial bones • Consists of 14 bones w/ only mandible and vomer unpaired • Others include maxillae, lacrimals, nasals, zygomatics, inferior nasal conchae, and palatines (not pictured)

Mandible • Forms the lower jaw • Largest, strongest bone of the face • It has a body and two upwardly projecting sections called rami • Houses lower dentition

Mandible - landmarks • • Mandibular angle Mandibular notch Coronoid process Mandibular condyle Alveolar margin Mandible formina Mental formina Ramus of mandible

Maxillary bone • Forms upper jaw and central portion of facial skeleton • Fused medially • Articulates with all facial bones except mandible • Upper dentition • Forms 2/3 of hard palate of the mouth Zygomatic process Maxillary bone

Maxillary bones - landmarks • Alveolar margin – Upper dentition • Frontal process – Forms lateral aspects of nose • Zygomatic process – Articulates with zygomatic bone • Maxillary sinuses – (Fig. 7. 11)

Palatine bones • The horizontal plates forms the posterior portion of hard palate • Vertical plate forms part of the posterolateral wall of nasal cavity and a small portion of orbit

Palatine bones - landmarks • Horizontal plate – Posterior section of hard palate • Vertical plate – Part of the posteriolateral walls of nasal cavity • Orbital surface – Part of inferior medial aspect of orbit

Vomer • Forms part of the nasal septum • Discussed with the nasal cavity

Vomer - landmarks • Plow shape – Divides nasal septum into right and left parts

Inferior Nasal Conchae - Landmark • The Inferior nasal conchae is just one of three in the nasal cavity • Superior and middle concha are on the Ethmoid bone