ANATOMY OF THE SKULL -Autosaved-.pptx

ANATOMY OF THE HEAD T. E. ISAMOH  INTRODUCTION The head consist of the skull, face, scalp, teeth, brain, cranial nerves, meninges, special sense organs, and other structures such as blood vessels, lymphatics and fat.  The Skull The skull consists essent...

ANATOMY OF THE HEAD T. E. ISAMOH  INTRODUCTION The head consist of the skull, face, scalp, teeth, brain, cranial nerves, meninges, special sense organs, and other structures such as blood vessels, lymphatics and fat.  The Skull The skull consists essentially of two parts: the cranial skeleton and the facial skeleton.  The cranial skeleton consists of 8 bones –(1) Frontal Bone –(2) TemporalBones –(2) Parietal Bones –(1) Occipital Bone –(1) Sphenoid Bone –(1) Ethmoid Bone Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  Facial Subdivisions of the Skull. Face: Consists of 14 bones (2) Maxilla (2) Zygomatic bones (2) Lacrimal bones (2) Palatine bones (2) Nasal bones (2) Inferior nasal conchae (1) Vomer (1) Mandible  BONES OF THE SKULL ARE FLAT. THE JOINTS BETWEEN THE BONES ARE CALLED SUTURES( INTERLOCKING AND IMMOVABLE) 1) CORONAL SUTURE 2) SAGITTAL SUTURE 3) LAMBDOID SUTURE 4) SQUAMOUS SUTURE Squamous Suture: Form boundaries between temporal bones and parietal bones Lambdoid Suture: separates occipital from parietal bones  Cranium frontal bone coronal suture parietal bone sagittal suture lambdoidal suture occipital bone Coronal Suture attaches frontal bone to parietal bones. Sagittal Suture is between the parietal bones and extends from lambdoid suture to coronal suture. Frontal Bone 10  Frontal Bone The large bone that makes up the forehead and supplies the upper edge and roof of the orbit (eye socket). 11  Landmarks: – Squama: flat portion that forms Frontal Bone the forehead – Supraorbital margin: ridge under the eyebrow, forming the upper part of the orbit (eye socket) – Supraorbital foramen: small hole within supraorbital margin for supraorbital vessels & nerve – Frontal sinuses: hollow spaces behind the squama, act as sound chambers to give the voice resonance. 12  Frontal Bone The frontal bone articulates (comes together) with a number of other bones including the parietal, nasal, ethmoid, maxillary, and zygomatic bones. 13  Temporal Bones A large irregular bone situated at the base and side of the skull. The temporal bone is connected with the mandible via the temporomandibular (TM) joint. 14 Temporal bone has the following parts: 1- Squamous part 2- Mastoid /petrous part. 3- Tympanic part Has the following processes: 1- Mastoid process. 2- Styloid process. 3- Zygomatic process Marks of the Temporal Bones Squamous part: borders the squamous suture. Petrous part: internal, forming part of the floor of the cranium. Contains the internal auditory meatus (opening to the ear canal) and encloses structures of the inner ear(auditory ossicles). Tympanic part : lies the external acoustic meatus, styloid process , mastoid process  Mastoid process: bony prominence behind the external auditory meatus. It contains mastoid air cells Styloid process: looks like an elephant’s tusk located between the mastoid process and the jaw. Acts as a point of attachment for muscles and ligaments. Zygomatic process: It articulates with temporal process of zygomatic bone to form zygomatic arch (cheekbone) Temporal Bones 18  Parietal Bones The main bone on the side of the skull. The word "parietal" comes from the Latin "parietalis" meaning "belonging to the wall.“ Form part of the superior and lateral surface of the cranium. 19 Articulation The parietal bones articulate with each other via the sagittal suture Occipital Frontal Temporal Sphenoid Bony landmarks Superior temporal line Inferior temporal line Parietal foramen Bony landmarks SUPERIOR TEMPORAL LINE Superior temporal line: It serves as INFERIOR TEMPORAL an attachment point for LINE temporal fascia that covers the temporalis muscle. Inferior temporal line: for attachment of temporalis muscle. PARIETAL FORAMEN: a hole found along the posterior aspect of the bone, next to the sagittal suture. Passageway for an emissary vein. Not always present and varies in size. PARIETAL FORAMEN Occipital Bone Forms the posterior and inferior surfaces of the cranium ARTICULATIONS =Parietal bones =Temporal bones = Sphenoid = First cervical vertebra (atlas) Bony landmarks  External occipital protuberance: attachment site of the ligamentum nuchae and the trapezius m.; its highest point is called the inion External occipital crest: for attachment of nuchal ligament. Occipital condyles: articulates with the superior facets of the atlas vertebra. Superior and inferior nuchal lines : sites for attachment of muscles and ligaments. Hypoglossal canal: transmit hypoglossal nerve. Foramen magnum: large hole,  Sphenoid bone The Sphenoid bone = Forms part of the floor of the cranium = Unites cranial and facial bones = Strengthens sides of the skull = Contains sphenoidal sinuses Articulations Ethmoid Frontal bone Occipital bone Parietal bone Temporal bone Palatine bones Zygomatic bones Maxillae Vomer The sphenoid bone is made up of 1- A centrally placed body. 2- Greater and lesser wings projecting laterally. 3- Two downward projecting pterygoid processes. Each process consists of a medial plate and a lateral plate separated by the pterygoid fossa. Sella turcica Saddle-shaped enclosure on the superior surface of the body made up of 1. Tuberculum sellae 2. Hypophyseal fossa 3. Dorsum sellae 4. Posterior clinoid process Hypophyseal fossa A depression within the sella turcica that holds the pituitary gland Sella turcica Saddle-shaped enclosure on the superior surface of the body made up of 1. Tuberculum sellae 2. Hypophyseal fossa 3. Dorsum sellae 4. Posterior clinoid process Hypophyseal fossa A depression within the sella turcica that holds the pituitary gland Sphenoidal sinuses Lies on either side of the body inferior to the sella turcica Lesser wings Lies anterior to the sella turcica Greater wings Forms part of the cranial floor, Sphenoidal spine and Posterior wall of the orbit Pterygoid processes Form pterygoid plates for attachment of muscles of the lower jaw and soft palate. Foramina: middle cranial  Ethmoid bone Forms anteromedial floor of the cranium  Roof of the nasal cavity  Part of the nasal septum and medial orbital wall  Contains ethmoidal air cells (network of sinuses) Articulations Frontal bone Sphenoid Nasal bone Lacrimal bone Palatine bone Maxillary bones Inferior nasal conchae Vomer Three Parts of the Ethmoid The cribriform plate horizontal plate in the cranial floor and roof of the nasal cavity that articulates with the frontal bone. It contains many small holes that transmit the olfactory nerves and the crista galli(attachment for falx cerebri) The two lateral masses ethmoidal air cells Superior nasal Bones of the Face 34  Zygomatic Bones Is also called zygoma, cheek & malar bones Forms the prominence of the cheeks Forms the lateral and inferior rim of the orbit and parts of the temporal and infratemporal fossæ Articulates with the: –Frontal –Sphenoid –Temporal –Maxilla  Zygomatic Bones Landmark On the lateral aspect of each zygomatic bone is a small foramen called zygomaticofacial foramen which transmit nerve of the same name, a branch of maxillary nerve Temporal process of the zygomatic bone meets the zygomatic process of the temporal bone to form the zygomatic arch. Applied Anatomy of Zygomatic Bone Malar flush: This is redness of the skin covering the zygomatic prominence and is associated with a rise in temperature in various fevers occuring with certain diseases such as tuberculosis  The Nasal Bones Functions of the nasal bones 1. Forms the bridge of the nose 2. Connect to cartilages of the distal part of the nose (external nares) Articulations of the nasal bones Ethmoid Frontal bone With other nasal bone Maxillae Bones forming the nasal cavity  The Vomer Located in the mid saggital line. Forms the inferior portion of the bony nasal septum Articulations of the vomer Sphenoid Ethmoid Palatine bones vome Maxillae r Cartilaginous part of the nasal septum  MAXILLA: Forms the part of the face between the orbit and the upper teeth. Contribute to the inferior and medial rim of the orbit. Inferiorly, each maxilla ends as the alveolar process which contains the teeth and forms the upper jaw. Articulations of the Maxillae Frontal bones Ethmoid All other facial bones except the mandible Functions of the maxillae 1. Support upper teeth 2. Forms inferior orbital rim 3. Forms lateral margins of external nares 4. Forms upper jaw and hard palate 5. Contain maxillary sinuses (largest sinuses) Bony landmarks of the Maxillae Orbital rim: protects eye and orbit Anterior nasal spine: attaches cartilaginous anterior nasal septum Alveolar processes: borders the mouth and supports upper teeth Palatine processes: form the hard palate (roof of mouth) Maxillary sinuses: to lighten bone Nasolacrimal canal: protects lacrimal sac and nasolacrimal duct  PALANTINE BONES Form the posterior portion of the hard palate. Contribute to the floors of the orbits Articulations Maxillae Sphenoid Ethmoid Inferior nasal conchae Vomer Divisions of the Palatine Bones Horizontal plate: which forms the posterior part of hard palate Perpendicular plate: extends from horizontal plate to orbital process of orbit floor The Lacrimal Bones The smallest facial bones Form part of the medial wall of the orbit Articulations Frontal bone Maxillae Ethmoid Bony landmark Lacrimal sulcus: location of the lacrimal sac leads to the nasolacrimal canal (between orbit and nasal cavity)  MANDIBLE The final bony we will discuss. Forms the lower jaw Articulations Mandibular fossae of the temporal bones. it consists of 1. the anterior body of mandible, 2. a posterior ramus of mandible and 3. the angle of mandible where the inferior margin of the mandible meets the posterior margin of the ramus  LANDMARK S The teeth are in the alveolar part of the body of mandible mental protuberance Mandibular foramen: inferior alveolar nerve & vessels passes through it to enter mandibular canal  A depression on the medial surface: for submandibular salivary gland. Mylohyoid line: for insertion of the mylohyoid muscle (floor of mouth). Mental foramen is on the lateral surface of the body. It transmit mental nerve. and on the superior part of the ramus a condylar and coronoid process extend upwards. The condylar process is involved in articulation of the mandible with the temporal bone coronoid process is the point of attachment for the temporalis muscle. Fracture of the mandible usually involves two fractures and they frequently occur on opposite side of the mandible, thus if one fracture is observed, a search should be made for another. Fracture of the coronoid process is uncommon and usually single Vertex – superior point of the cranium Bregma – junction of coronal and sagittal suture Naison – point where frontonasal and internasal sutures meet which in most people is related to a distinctly depressed area (bridge of the nose) Inion – most prominent point of external occipital protuberance Asterion – star shaped : located at the junction of three sutures – parietomastoid, occipitomastoid and lambdoid Lambda – junction of sagittal and lambdoid sutures Glabella: most anterior projecting part of the forehead Pterion: junction of the greater wing of sphenoid bone; squamous temporal, frontal and parietal bones; overlies course of anterior division of middle meningeal artery The pterion is an important clinical landmark, because it overlies the anterior branches of middle meningeal artery  A blow to the side of the head may fracture the thin bones forming the pterion, rupturing the anterior branch of the middle meningeal artery crossing the pterion The resulting hematoma (collection of blood) exerts pressure on the underlying cerebral cortex Untreated middle meningeal artery hemorrhage may cause death in a few hours SKULL OF A NEWBORN The skull of a newborn consists of five main bones: Two frontal bones, two parietal bones, and one occipital bone. These are joined by fibrous sutures, which allow movement that facilitates childbirth and brain growth. The major sutures of the skull include the following: Metopic, Coronal, Sagittal & Lambdoid sutures Metopic Suture extends from the top of the head down the middle of the forehead, toward the nose. The two frontal bone plates meet at the metopic suture. The metopic suture obliterate in the 8th year but in about 8% of people a remnant of it persist CORONAL SUTURE extends from ear to ear. Each frontal bone plate meets with a parietal bone plate at the coronal suture. SAGITTAL SUTURE extends from the front of the head to the back, down the middle of the top of the head. The two parietal bone plates meet at the sagittal suture.  lambdoid suture - extends across the back of the head. Each parietal bone plate meets the occipital bone plate at the lambdoid suture.  Sutures allow the bones to move during the birth process. They act like an expansion joint, allowing the bone to enlarge evenly as the brain grows and the skull expands, resulting in a symmetrically shaped head. However, if any of the sutures close too early (fuse prematurely), there may be no growth in that area, this may force growth to occur in another area or direction, resulting in an abnormal head shape. The obliteration of sutures between the bones of the calvaria begins between ages of 30 and 40 on the internal surface and approximately 10years later on the external surface FONTANELLES Fontanelles are soft spots on a baby's head which, during birth, enable the bony plates of the skull to flex, allowing the child's head to pass through the birth canal. Enables the physicians to determine the : 1. Progress of growth of the frontal and parietal bones 2. Degree of hydration of the infant ( a depressed fontanelle indicates dehydration) 3. Levels of intracrainial pressure. A bulging fontanelle indicates increased pressure on the brain Fontanelles allow the infant brain to be imaged using ultrasonography. There are six fontanelles a. Two in the median plane – anterior and posterior b. Two pairs on each side – the anterolateral or sphenoidal fontanelles &  posterolateral or mastoid fontanelles Anterior fontanelle: Is located at the junction of the sagittal, coronal and frontal (metopic) sutures, the future site of bregma Anterior fontanelle closes by 18 to 24 months Posterior fontanelle Is triangular bounded by the parietal bones anteriorly and occipital bone posteriorly. Located at the junction of the lambdoid and sagittal sutures, the future site of the lambda Posterior fontanelles close close during the first few months of life. ( by the end of the first year.) Sphenoidal or anterolateral fontanelle: Located between the sphenoid, parietal, temporal, and frontal bones Mastoid or posterolateral fontanelle Located between the temporal, occipital, and parietal bones. Sphenoidal fontanelles & mastoid fontanelles closes few weeks after birth  Internal surface of the base of the skull the internal surface of the cranial base has three large, 1. Anterior cranial fossa distinct depressions that lies at accommodates the frontal different levels forming the bowl- lobe of the brain shaped floor of the cranial cavity. They are: 2. Middle cranial fossa 1. Anterior cranial fossa contains two temporal 2. Middle cranial fossa lobes of brain 3. Posterior cranial fossa The anterior cranial fossa is at 3. Posterior cranial fossa is the highest level much wider than the and the posterior cranial fossa middle cranial fossa and it contains the occipital at the lowest level lobes of the brain  Anterior Cranial Fossa Anterior cranial fossa Boundaries: Anteriorly & laterally: frontal bone Middle: ethmoid bone Posteriorly: body and lesser wing of sphenoid bone Floor: orbital plate of the frontal bone Features seen 1. Frontal crest – a median bony extension of the frontal bone 2. Foramen cecum – emissary veins to superior sagittal sinus 3. Crista galli – median ridge bone 4. Cribiform plate – olfactory nerve (CN 1)  Applied anatomy Fracture of the anterior cranial fossa may cause bleeding and discharge of cerebrospinal fluid through the nose. It may also cause a condition called black eye which is produced by seeping of blood into the eyelid  Middle Cranial Fossa Middle cranial fossa Boundaries Anteriorly: posterior border of the lesser wing of sphenoid bone, anterior clinoid process Laterally: greater wings of sphenoid bone and squamous part of temporal bone Posteriorly: petrous part of temporal bone; dorsum sellae of the sphenoid bone Floor: body of sphenoid, greater wing of sphenoid and squamous and petrous parts of temporal bone Features seen 1. Sella turcica surrounded by anterior and posterior clinoid processes 2. Sella turcica is composed of three part namely a. Tuberculum sellae b. Hypophyseal fossa c. Dorsum sellae  Middle Cranial Fossa The Middle Cranial Fossa has foraminae namely 1. Superior orbital fissure – b/w greater and lesser wing: Ophthalmic vein, lacrimal, frontal and nasociliary branches of ophthalmic nerve, CN III, IV, VI. 2. Foramen rotundum - lies Posterolateral to the medial end of Superior Orbital Fissure – maxillary nerve 3. Foramen ovale – Posterolateral to foramen rotundum: Accessory meningeal artery, mandibular nerve and lesser petrosal nerve (occasionally) 4. Foramen spinosum – Posterolateral to foramen ovale: middle meningeal vessels/meningeal branch of mandibular nerve 5. Foramen lacerum – lies posteromedial to foramen ovale.  Applied anatomy The Middle cranial fossa is most commonly fractured. Fracture of the middle cranial fossa produces a) Bleeding and discharge of CSF through the ear b)Bleeding through the nose or mouth may occur due to involvement of the sphenoid bone c) VII & VIII cranial nerves may be damaged if the fracture also passes through the internal acoustic meatus. If semicircular canal is damaged, vertigo may occur d)Read more (Chaurasia’s volume 3. 4 th edition Pg 23.  Posterior Cranial Fossa Posterior cranial fossa Lodges the cerebellum, pons and medulla oblongata Boundaries; Anterior: dorsum sellae Anterolateral: petrous and mastiod part of temporal bone Posteriorly: internal occipital crest – occipital fossa; Internal occipital protuberance (confluence of sinuses Foramen magnum form the central part of the floor. Features seen 1. Groove for transverse and sigmoid sinuses  Foraminae Jugular foramen – base of the petrous ridge of the temporal bone: Internal jugular vein, inferior petrosal sinus and sigmoid sinus, CN IX, X, XI. Internal acoustic meatus – facial and vestibulocochlear nerve and labyrinthine vessels Hypoglossal canal- superior to the anterolateral margin of the foramen magnum. Hypoglossal nerve Foramen magnum: Spinal cord and its coverings, vertebral arteries; anterior and posterior spinal arteries & spinal accessory N  Applied anatomy Fracture of the posterior cranial fossa causes bruising over the mastoid region extending over the sternocledomastoid muscle.  TEMPORAL FOSSA The temporal fossa is a shallow depression on the side of the skull bounded by the temporal lines and terminating below the level of the zygomatic arch. The temporal bone, the sphenoid bone, the parietal bone and the frontal bone contribute to its concave wall. Sinuses Several bones of the skull contain air-filled chambers called sinuses. Sinuses have two major functions: They make the bone much lighter than it would otherwise be. The mucous membrane lining them produces mucus that moistens and cleans the air in and adjacent to the sinus.  Bones CRANIAL FOSSAE Frontal Ethmoid Anterior Sphenoid Temporal Middle Parietal Posterior Occipital Anterior Cranial Fossa Middle Cranial Fossa Posterior Cranial Fossa Anterior view: Glabella: Includes:most anterior projecting 1- partThe forehead of the forehead 2- The orbits 3- The nasal region 4- the part of the face between the orbit and the upper jaw 5- The lower jaw The bones of the skull protects the brain and guards the entrances to the digestive and respiratory systems. Glabella: most anterior projecting part of the forehead FORAMINA BONE STRUCTURE Supra-orbital foramen Frontal Supraorbital vessels & nerve bone Superior orbital fissure Sphenoid Superior ophthalmic vein, oculomotor nerve(III), trochlear nerve (IV), lacrimal, frontal and nasociliary branches of ophthalmic nerve (V1), abducent nerve (VI) FORAMINA BONE STRUCTURE OPTIC CANAL SPHENOID BONE OPTIC NERVE & OPHTHALMIC ARTERY INFERIOR ORBITAL BETWEEN SPHENOID & INFERIOR ORBITAL FISSURE MAXILLA VESSELS & NERVE, inferior ophthalmic veins, INFRA-ORBITAL MAXILLA INFRAORBITAL VESSELS FORAMEN & NERVE MENTAL FORAMEN MANDIBLE MENTAL VESSELS & NERVE Posterior view of the skull  The Skull Figure 7–3b The Adult Skull. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  The Skull Figure 7–3a The Adult Skull. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  The Skull Figure 7–3c The Adult Skull. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings  The Skull Figure 7–3e The Adult Skull. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings FORAMINA BONE VESSELS NERVES Perforations in ethmoid Olfactory nerve cribiform plate FORAMEN SPHENOID MAXILLARY NERVE ROTUNDUM FORAMEN OVALE SPHENOID ACCESSORY Mandibular MENINGEAL nerve(v3), lesser ARTERY, petrosal N (occasionally) FORAMEN SPHENOID BONE MIDDLE MENINGEAL SPINOSUM MENINGEAL BRANCH OF THE ARTERY, MANDIBULAR NERVE (V3) FORAMEN B/W TEMPORAL, FORAMEN IS LACERUM SPHENOID AND FILLED WITH OCCIPITAL BONE CARTILAGE DURING LIFE FORAMINA BONE VESSELS NERVES FORAMEN SPHENOID BONE MIDDLE MENINGEAL SPINOSUM MENINGEAL BRANCH OF THE ARTERY, MANDIBULAR NERVE (V3) FORAMEN B/W TEMPORAL, FORAMEN IS LACERUM SPHENOID AND FILLED WITH OCCIPITAL BONE CARTILAGE DURING LIFE FORAMINA BONE VESSELS NERVES FORAMEN OCCIPITAL Spinal cord and its Anterior and MAGNUM BONE coverings, vertebral posterior spinal A arteries & spinal accesory N JUGULAR OCCIPITAL Internal JUGULAR CN IX through XI FORAMEN BONE VEIN HYPOGLOSSAL OCCIPITAL HYPOGLOSSAL CANAL BONE NERVES Carotid canal Sphenoid & Internal carotid temporal bone artery Bones forming the orbit The frontal bone: Forms the superior part of the rim of each orbit. Has the following features: 1- Superciliary arches (two raised bony ridges) 2- The glabella, a depression located between these two arches. 3- Supra orbital foramen located within the medial part of the superior rim of each orbit. Supraorbital vessels and nerve passes through it. 4- A zygomatic process that articulates with the frontal process of the zygomatic bone. Bony landmarks of the frontal bone Frontal squama (forehead) Supra-orbital margin (protects eye) Lacrimal fossa (for tear ducts) Frontal sinuses  Blow to the superior orbital margin may lacerate the skin and cause profuse bleeding Bruising of the skin surrounding the orbit causes tissue fluid and blood to accumulate into the surrounding connective tissue which gravitates into the superior (upper) eyelid and around the eye (black eye) Squamous part: zygomatic process, articular tubercle , mandibular fossa Tympanic part : external acoustic meatus, styloid process , mastoid process Petrous part: internal acoustic pore Functions of the temporal bones 1. Forms part of lateral walls of cranium and zygomatic arches 2. Articulate with mandible 3. It surrounds and protect inner ear 4. Provided attachment for muscles of jaws and head Articulations of the temporal bones -Zygomatic bone--Sphenoid =Parietal bone =Occipital bone = Mandible  Sphenoid bone The Sphenoid Functions of the Sphenoid = Forms part of the floor of the cranium = Unites cranial and facial bones = Strengthens sides of the skull = Contains sphenoidal sinuses Articulations of the Sphenoid Ethmoid Frontal bone Occipital bone Parietal bone Temporal bone Palatine bones Zygomatic bones Maxillae Vomer The sphenoid bone is made up of 1- A centrally placed body. 2- Greater and lesser wings projecting laterally. 3- Two downward projecting pterygoid processes. Each process consists of a medial plate and a lateral plate separated by the pterygoid fossa. Sella turcica Saddle-shaped enclosure on the superior surface of the body made up of 1. Tuberculum sellae 2. Hypophyseal fossa 3. Dorsum sellae 4. Posterior clinoid process Hypophyseal fossa A depression within the sella turcica that holds the pituitary gland Sphenoidal sinuses Lies on either side of the body inferior to the sella turcica Lesser wings Lies anterior to the sella turcica Greater wings Forms part of the cranial floor, Sphenoidal spine and Posterior wall of the orbit Pterygoid processes Form pterygoid plates for attachment of muscles of the lower jaw and soft palate  Ethmoid bone Functions of the ethmoid  Forms anteromedial floor of the cranium  Roof of the nasal cavity  Part of the nasal septum and medial orbital wall  Contains ethmoidal air cells (network of sinuses) Three Parts of the Ethmoid The cribriform plate Floor of the cranium Roof of the nasal cavity Contains the crista galli The two lateral masses ethmoidal air cells Superior nasal conchae Middle nasal conchae Articulations of the Ethmoid Frontal bone Sphenoid Nasal bone Lacrimal bone Palatine bone Maxillary bones Inferior nasal conchae Vomer Bones forming the orbit  Zygomatic Bones Is also called zygoma, cheek & malar bones Forms the prominence of the cheeks Forms the lateral and inferior rim of the orbit Articulates with the: – Frontal – Sphenoid – Temporal – Maxilla On the lateral aspect of each zygomatic bone is a small foramen called zygomaticofacial foramen which transmit nerve of the same name, a branch of maxillary nerve – landmark – Temporal process of the zygomatic bone meets the zygomatic process of the temporal bone to form the zygomatic arch. Applied Anatomy of Zygomatic Bone Malar flush: This is redness of the skin covering the zygomatic prominence and is associated with a rise in temperature in various fevers occuring with certain diseases such as tuberculosis FIG 3 - LeFort lines used for classifying fractures of the middle third of the face. Le Fort 1: horizontal fracture along the maxilla located just superior to the alveolar process, crossing the nasal septum. Le Fort 2: Fracture along the posterolatel part of the maxillary sinus, superomedially through the infraobrital foramen and lacrimal bone to the bridge of the nose. As a result the medial part of the face, hard palate & alveolar processes is separated from the skull FIG 3 - LeFort lines used for classifying fractures of the middle third of the face. Le Fort 3: horizontal fracture that passes through superior orbital fissure, ethmiod, nasal bones and extends laterally through the greater wing of sphenoid bone and frontozygomatic suture. It causes the maxillae and zygomatic bone to separate from the rest of the skull Fracture of the neck of mandible may be associated with dislocation of temperomandibular joint on the same side Fracture of the angle of mandible – usually oblique and may involve the alveolus of 3rd molar tooth Fracture of the body of mandible frequently pass through the alveolus of a canine tooth. FORAMINA BONE VESSELS NERVES FORAMEN SPHENOID BONE MIDDLE MENINGEAL SPINOSUM MENINGEAL BRANCH OF THE ARTERY, MANDIBULAR NERVE (V3) FORAMEN B/W TEMPORAL, FORAMEN IS LACERUM SPHENOID AND FILLED WITH OCCIPITAL BONE CARTILAGE DURING LIFE Carotid TEMPORAL BONE internal carotid artery canal: FORAMINA BONE VESSELS NERVES FORAMEN OCCIPITAL Spinal cord and its Anterior and MAGNUM BONE coverings, vertebral posterior spinal A arteries & spinal accessory N JUGULAR OCCIPITAL JUGULAR VEIN FORAMEN BONE HYPOGLOSSAL OCCIPITAL HYPOGLOSSAL CANAL BONE NERVE Olfactory cribrif olfactory foramina orm nerves plate FORAMINA BONE VESSELS NERVES Stylomastoi TEMPORAL Stylomastoid FACIAL NERVE branch of the d foramen posterior auricular artery External PETROUS PART OF TEMPORAL VESTIBULOCOCHL EAR AND FACIAL / Internal NERVE acoustic meatus The Frontal bone Functions of the frontal bone 1. Forms the anterior cranium and upper eye sockets 2. Contains frontal sinuses Articulations of the frontal Bone Parietal bone Maxilla Ethmoid Lacrimal bone Zygomatic bone Sphenoid Nasal bone The site of union between the coronal and sagittal suture is called the Bregma which is the site of anterior fontanelle. The site of union between the sagittal and lambdoid suture is called the lambda and is the site for posterior fontanelle. lambda bregma