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Facial BonesDr. Ahmed Alsharef Farah
Dr. Ahmed Alsharef Farah 1
Facial bones:
• The face is made up of 14 facial bones.• They consist of the:- Nasal (2).- Lacrimal (2).- Palatine (2).- Maxilla (2).- Zygoma (2).- Inferior nasal conchae (2).- Vomer (1).- Mandible (1).
Dr. Ahmed Alsharef Farah 2
Anterior view of facial bones.
Dr. Ahmed Alsharef Farah 3
Sagittal view of facial bones.
Dr. Ahmed Alsharef Farah 4
Sagittal view of orbit and facial bones.Dr. Ahmed Alsharef Farah 5
3D CT of oblique aspect of facial bones.Dr. Ahmed Alsharef Farah 6
Nasal Bones:
• The two nasal bones form the bony bridge ofthe nose and articulate with four bones:
- Frontal bone.- Ethmoid bones of the cranium.- The opposite nasal bone.- Maxilla.
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Coronal CT of nasal bones.Dr. Ahmed Alsharef Farah 8
Lacrimal Bones:
• Posterior to the nasal bones and maxilla are thelacrimal bones, which are situated on themedial wall of each orbit.
• The junction between the lacrimal bones andthe maxillae forms the lacrimal groove, whichaccommodates the lacrimal sacs that are part ofthe drainage route for excess lacrimal fluid(tears).
Dr. Ahmed Alsharef Farah 9
Sagittal view of orbit and facial bones.Dr. Ahmed Alsharef Farah 10
Palatine Bones:
• The palatine bones are located in the posterioraspect of the nasal cavity between the maxillaand the pterygoid process of the sphenoid.
• The palatine bones consist of a horizontalportion and a perpendicular portion.
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• The horizontal portion of the palatine bonesjoins anteriorly with the palatine process of themaxilla to form the hard palate.
• The vertical portion extends to form a segmentof the lateral wall of the nasal cavity and themedial wall of the orbit.
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Inferior view of facial bones and hard palate.Dr. Ahmed Alsharef Farah 13
Axial CT of hard palate.Dr. Ahmed Alsharef Farah 14
Maxillary Bones:
• The largest immovable facial bones are themaxillary bones, which fuse at the midline toform a pointed process termed the anteriornasal spine.
• An opening on the anterior aspect of themaxilla is the infraorbital foramen, whichtransmits the infraorbital nerve and bloodvessels.
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• The maxillary bones contain the large maxillarysinuses and four processes:
- Frontal process.- Zygomatic process.- Alveolar process.- Palatine process.
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Coronal CT of maxilla and zygoma.Dr. Ahmed Alsharef Farah 17
• The inferior border of the maxilla has severaldepressions that form the alveolar process,which accepts the roots of the teeth.
• The palatine process of the maxilla extendsposteriorly to form three fourths of the hardpalate. The posterior one fourth of the hardpalate is created by the horizontal portion ofthe palatine bones.
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Axial CT of alveolar process of maxilla.Dr. Ahmed Alsharef Farah 19
Zygomatic Bones:
• The zygomatic bones (zygoma or malar)create the prominence of the cheek andcontribute to the lateral portion of the bonyorbit.
• The temporal process of the zygomatic boneextends posteriorly to join the zygomaticprocess of the temporal bone to form thezygomatic arch.
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Axial CT of facial bones.Dr. Ahmed Alsharef Farah 21
Axial CT of facial bones and ethmoid sinuses.Dr. Ahmed Alsharef Farah 22
Inferior Nasal Conchae:
• The inferior nasal conchae (inferior nasalturbinates) arise from the maxillary bones andproject horizontally into the nasal cavity.
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Axial CT of facial bones.Dr. Ahmed Alsharef Farah 24
• These conchae in conjunction with the superiorand middle nasal conchae of the ethmoidbone divide the nasal cavity into threeopenings or meati, termed:
- Superior.- Middle.- inferior.
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Sagittal view of nasal meati.Dr. Ahmed Alsharef Farah 26
Sagittal CT reformat of nasal meati.Dr. Ahmed Alsharef Farah 27
Vomer:
• The vomer is an unpaired facial bone located onthe midsagittal line.
• The vomer forms the inferior portion of thebony nasal septum as it projects superiorly toarticulate with the perpendicular plate of theethmoid bone.
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Coronal CT of vomer.Dr. Ahmed Alsharef Farah 29
Mandible:
• The largest facial bone is the mandible.• This bone is composed primarily of horizontal
and vertical portions.• The angle created by the junction of these two
portions is termed the gonion.
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• The curved horizontal portion, called thebody, contains an alveolar process (similar tothe maxilla) that receives the roots of the teethof the lower jaw.
• The mental foramina extend through the bodyof the mandible and allow passage of themental artery and nerve.
• The vertical portion of the mandible is calledthe ramus.
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Lateral view of mandible.Dr. Ahmed Alsharef Farah 32
3D CT of lateral aspect of mandible.Dr. Ahmed Alsharef Farah 33
Coronal CT of mandibular rami.Dr. Ahmed Alsharef Farah 34
• Each ramus has two processes at its superiorportion:
- Coronoid process.- Condyloid process (condyle).• They are separated by a concave surface called
the mandibular notch.
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Lateral view of mandible.Dr. Ahmed Alsharef Farah 36
Axial CT of mandibular rami.Dr. Ahmed Alsharef Farah 37
Axial CT of mandibular condyles.Dr. Ahmed Alsharef Farah 38
• The coronoid process serves as an attachmentsite for the temporalis and masseter muscles.
• The condyloid process articulates with themandibular fossa of the temporal bone toform the temporomandibular joint (TMJ).
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Temporomandibular joint:
• The temporomandibular joint (TMJ) is amodified hinge joint that allows for thenecessary motions of mastication.
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Bony Anatomy:
• The mandibular fossa and articular eminenceof the temporal bone form the superiorarticulating surface for the mandibularcondyloid process of mandible (condyle).
• The articular eminence creates the anteriorboundary of the joint, preventing the forwarddisplacement of the mandibular condyle.
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Lateral view of temporomandibular joint.Dr. Ahmed Alsharef Farah 42
Sagittal CT reformat of temporomandibular joint.Dr. Ahmed Alsharef Farah 43
Articular Disk and Ligaments:
• The articular disk, frequently called themeniscus, is shaped like a bowtie and isinterposed between the mandibular condyleand fossa to act as a shock absorber during jawmovement.
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Sagittal, T1-weighted MRI of TMJ and articular disk.Dr. Ahmed Alsharef Farah 45
• The articular disk is attached to the medial andlateral surfaces of the condyle by the collateralligaments.
• Lateral stability is provided by the temporo-mandibular ligament (lateral ligament).
• Additionally, this ligament restricts the posteriormovement of the condyle and articular disk.
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Coronal view of TMJ and collateral ligaments.Dr. Ahmed Alsharef Farah 47
Coronal, T1-weighted MRI of TMJ.Dr. Ahmed Alsharef Farah 48
Sagittal view of TMJ and lateral ligament.Dr. Ahmed Alsharef Farah 49
Muscles:
• The cooperative actions of four muscles locatedon each side of the TMJ provide the movementof the mandible and are collectively referred toas the muscles of mastication.
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• The fan-shaped temporalis muscle originates onthe temporal fossa, inserts on the coronoidprocess of the mandible, and elevates themandible.
• The masseter muscle is the strongest muscle ofthe jaw, arising from the zygomatic arch andinserting on the ramus and angle of themandible. Its actions include elevation of themandible.
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Muscles of mastication.Dr. Ahmed Alsharef Farah 52
Coronal, T1-weighted MRI of muscles of mastication.Dr. Ahmed Alsharef Farah 53
• The pterygoid muscles (medial and lateral)originate from the pterygoid processes of thesphenoid bone and insert on the angle of themandible and condylar process, respectively.
• The medial pterygoid muscle acts to close thejaw, whereas the lateral pterygoid muscleopens the jaw and protrudes and moves themandible from side to side.
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Muscles of mastication.Dr. Ahmed Alsharef Farah 55
Axial, T1-weighted MRI of pterygoid muscles.Dr. Ahmed Alsharef Farah 56
Axial CT of TMJ and muscles of mastication.Dr. Ahmed Alsharef Farah 57
Paranasal sinuses
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Paranasal sinuses:
• The paranasal sinuses are air-containingcavities within the facial bones and skull thatcommunicate with the nasal cavity.
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• The sinuses are named after the bones in whichthey originate:
- Ethmoid.- Maxillary.- Sphenoid.- Frontal.
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Anterior view of paranasal sinuses.Dr. Ahmed Alsharef Farah 61
Lateral view of paranasal sinuses.Dr. Ahmed Alsharef Farah 62
Ethmoid sinuses:
• The ethmoid sinuses are contained within thelateral masses (labyrinths) of the ethmoidbone.
• The Ethmoid sinuses are divided into anteriorand posterior groups by the basal lamella ofthe middle conchae (turbinate).
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Axial CT of sphenoid and ethmoid sinuses.Dr. Ahmed Alsharef Farah 64
Coronal CT of ethmoid and maxillary sinuses.Dr. Ahmed Alsharef Farah 65
Maxillary sinuses:
• The paired maxillary sinuses (Antrum ofHighmore) are located within the body of themaxilla.
• These triangular cavities are the largest of theparanasal sinuses in adults.
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Axial CT of maxillary sinuses.Dr. Ahmed Alsharef Farah 67
Sphenoid sinuses:
• Sphenoid sinuses are normally paired andoccupy the body of the sphenoid bone justbelow the sella turcica.
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Sagittal, T1-weighted MRI of sphenoid sinus.
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Coronal, T1-weighted MRI of sphenoid sinuses.Dr. Ahmed Alsharef Farah 70
Coronal CT of sphenoid sinuses.Dr. Ahmed Alsharef Farah 71
Frontal sinuses:
• The frontal sinuses are located within thevertical portion of the frontal bone.
• These sinuses are typically paired and areseparated along the sagittal plane by a septum.
• The frontal sinuses are rarely symmetric,vary greatly in size.
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Coronal CT of frontal sinuses.
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The End
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