Facial Bones

Dr. 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 Dr. Ahmed Alsharef Farah 3 Anterior view of facial bones. Dr. Ahmed Alsharef Farah 4 Sagittal view of facial bones. Dr. Ahmed Alsharef Farah 5 Sagittal view of orbit and facial bones. Dr. Ahmed Alsharef Farah 6 3D CT of oblique aspect of facial bones. Nasal Bones:

• The two nasal bones form the bony bridge of the nose and articulate with four bones: - Frontal bone. - Ethmoid bones of the cranium. - The opposite nasal bone. - Maxilla.

Dr. Ahmed Alsharef Farah 7 Dr. Ahmed Alsharef Farah 8 Coronal CT of nasal bones. Lacrimal Bones:

• Posterior to the nasal bones and maxilla are the lacrimal bones, which are situated on the medial wall of each orbit. • The junction between the lacrimal bones and the maxillae forms the lacrimal groove, which accommodates the lacrimal sacs that are part of the drainage route for excess lacrimal fluid (tears).

Dr. Ahmed Alsharef Farah 9 Dr. Ahmed Alsharef Farah 10 Sagittal view of orbit and facial bones. Palatine Bones:

• The palatine bones are located in the posterior aspect of the nasal cavity between the maxilla and the pterygoid process of the sphenoid. • The palatine bones consist of a horizontal portion and a perpendicular portion.

Dr. Ahmed Alsharef Farah 11 • The horizontal portion of the palatine bones joins anteriorly with the palatine process of the maxilla to form the hard palate. • The vertical portion extends to form a segment of the lateral wall of the nasal cavity and the medial wall of the orbit.

Dr. Ahmed Alsharef Farah 12 Dr. Ahmed Alsharef Farah 13 Inferior view of facial bones and hard palate. Dr. Ahmed Alsharef Farah 14 Axial CT of hard palate. Maxillary Bones:

• The largest immovable facial bones are the maxillary bones, which fuse at the midline to form a pointed process termed the anterior nasal spine. • An opening on the anterior aspect of the maxilla is the infraorbital foramen, which transmits the infraorbital nerve and blood vessels.

Dr. Ahmed Alsharef Farah 15 • The maxillary bones contain the large maxillary sinuses and four processes: - Frontal process. - Zygomatic process. - Alveolar process. - Palatine process.

Dr. Ahmed Alsharef Farah 16 Dr. Ahmed Alsharef Farah 17 Coronal CT of maxilla and zygoma. • The inferior border of the maxilla has several depressions that form the alveolar process, which accepts the roots of the teeth. • The palatine process of the maxilla extends posteriorly to form three fourths of the hard palate. The posterior one fourth of the hard palate is created by the horizontal portion of the palatine bones.

Dr. Ahmed Alsharef Farah 18 Dr. Ahmed Alsharef Farah 19 Axial CT of alveolar process of maxilla. Zygomatic Bones:

• The zygomatic bones (zygoma or malar) create the prominence of the cheek and contribute to the lateral portion of the bony orbit. • The temporal process of the zygomatic bone extends posteriorly to join the zygomatic process of the temporal bone to form the zygomatic arch.

Dr. Ahmed Alsharef Farah 20 Dr. Ahmed Alsharef FarahAxial CT of facial bones. 21 Dr. Ahmed Alsharef Farah 22 Axial CT of facial bones and ethmoid sinuses. Inferior Nasal Conchae:

• The inferior nasal conchae (inferior nasal turbinates) arise from the maxillary bones and project horizontally into the nasal cavity.

Dr. Ahmed Alsharef Farah 23 Dr. Ahmed Alsharef FarahAxial CT of facial bones. 24 • These conchae in conjunction with the superior and middle nasal conchae of the ethmoid bone divide the nasal cavity into three openings or meati, termed: - Superior. - Middle. - inferior.

Dr. Ahmed Alsharef Farah 25 Dr. Ahmed Alsharef Farah 26 Sagittal view of nasal meati. Dr. Ahmed AlsharefSagittal Farah CT reformat of nasal meati. 27 Vomer:

• The vomer is an unpaired facial bone located on the midsagittal line. • The vomer forms the inferior portion of the bony nasal septum as it projects superiorly to articulate with the perpendicular plate of the ethmoid bone.

Dr. Ahmed Alsharef Farah 28 Dr. Ahmed Alsharef Farah 29 Coronal CT of vomer. 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.

Dr. Ahmed Alsharef Farah 30 • The curved horizontal portion, called the body, contains an alveolar process (similar to the maxilla) that receives the roots of the teeth of the lower jaw. • The mental foramina extend through the body of the mandible and allow passage of the mental artery and nerve. • The vertical portion of the mandible is called the ramus.

Dr. Ahmed Alsharef Farah 31 Dr. Ahmed Alsharef Farah 32 Lateral view of mandible. Dr. Ahmed Alsharef Farah 33 3D CT of lateral aspect of mandible. Dr. Ahmed Alsharef Farah 34 Coronal CT of mandibular rami. • Each ramus has two processes at its superior portion: - Coronoid process. - Condyloid process (condyle). • They are separated by a concave surface called the mandibular notch.

Dr. Ahmed Alsharef Farah 35 Dr. Ahmed Alsharef Farah 36 Lateral view of mandible. Dr. Ahmed Alsharef Farah 37 Axial CT of mandibular rami. Dr. Ahmed Alsharef Farah 38 Axial CT of mandibular condyles. • The coronoid process serves as an attachment site for the temporalis and masseter muscles. • The condyloid process articulates with the mandibular fossa of the temporal bone to form the temporomandibular joint (TMJ).

Dr. Ahmed Alsharef Farah 39 Temporomandibular joint:

• The temporomandibular joint (TMJ) is a modified hinge joint that allows for the necessary motions of mastication.

Dr. Ahmed Alsharef Farah 40 Bony Anatomy:

• The mandibular fossa and articular eminence of the temporal bone form the superior articulating surface for the mandibular condyloid process of mandible (condyle). • The articular eminence creates the anterior boundary of the joint, preventing the forward displacement of the mandibular condyle.

Dr. Ahmed Alsharef Farah 41 Dr. AhmedLateral Alsharef Farahview of temporomandibular joint. 42 Dr. Ahmed Alsharef Farah 43 Sagittal CT reformat of temporomandibular joint. Articular Disk and Ligaments:

• The articular disk, frequently called the meniscus, is shaped like a bowtie and is interposed between the mandibular condyle and fossa to act as a shock absorber during jaw movement.

Dr. Ahmed Alsharef Farah 44 Dr. Ahmed Alsharef Farah 45 Sagittal, T1-weighted MRI of TMJ and articular disk. • The articular disk is attached to the medial and lateral surfaces of the condyle by the collateral ligaments. • Lateral stability is provided by the temporo- mandibular ligament (lateral ligament). • Additionally, this ligament restricts the posterior movement of the condyle and articular disk.

Dr. Ahmed Alsharef Farah 46 Dr. AhmedCoronal Alsharef view Farah of TMJ and collateral ligaments. 47 Dr. Ahmed Alsharef Farah 48 Coronal, T1-weighted MRI of TMJ. Dr. AhmedSagittal Alsharef Farahview of TMJ and lateral ligament. 49 Muscles:

• The cooperative actions of four muscles located on each side of the TMJ provide the movement of the mandible and are collectively referred to as the muscles of mastication.

Dr. Ahmed Alsharef Farah 50 • The fan-shaped temporalis muscle originates on the temporal fossa, inserts on the coronoid process of the mandible, and elevates the mandible. • The masseter muscle is the strongest muscle of the jaw, arising from the zygomatic arch and inserting on the ramus and angle of the mandible. Its actions include elevation of the mandible.

Dr. Ahmed Alsharef Farah 51 Dr. Ahmed Alsharef FarahMuscles of mastication. 52 Dr. Ahmed Alsharef Farah 53 Coronal, T1-weighted MRI of muscles of mastication. • The pterygoid muscles (medial and lateral) originate from the pterygoid processes of the sphenoid bone and insert on the angle of the mandible and condylar process, respectively. • The medial pterygoid muscle acts to close the jaw, whereas the lateral pterygoid muscle opens the jaw and protrudes and moves the mandible from side to side.

Dr. Ahmed Alsharef Farah 54 Dr. Ahmed Alsharef FarahMuscles of mastication. 55 Dr. Ahmed Alsharef Farah 56 Axial, T1-weighted MRI of pterygoid muscles. Dr. Ahmed Alsharef Farah 57 Axial CT of TMJ and muscles of mastication. Paranasal sinuses

Dr. Ahmed Alsharef Farah 58 Paranasal sinuses:

• The paranasal sinuses are air-containing cavities within the facial bones and skull that communicate with the nasal cavity.

Dr. Ahmed Alsharef Farah 59 • The sinuses are named after the bones in which they originate: - Ethmoid. - Maxillary. - Sphenoid. - Frontal.

Dr. Ahmed Alsharef Farah 60 Dr. Ahmed Alsharef Farah 61 Anterior view of paranasal sinuses. Dr. Ahmed Alsharef Farah 62 Lateral view of paranasal sinuses. Ethmoid sinuses:

• The ethmoid sinuses are contained within the lateral masses (labyrinths) of the ethmoid bone. • The Ethmoid sinuses are divided into anterior and posterior groups by the basal lamella of the middle conchae (turbinate).

Dr. Ahmed Alsharef Farah 63 Dr. Ahmed Alsharef Farah 64 Axial CT of sphenoid and ethmoid sinuses. Dr. Ahmed Alsharef Farah 65 Coronal CT of ethmoid and maxillary sinuses. Maxillary sinuses:

• The paired maxillary sinuses (Antrum of Highmore) are located within the body of the maxilla. • These triangular cavities are the largest of the paranasal sinuses in adults.

Dr. Ahmed Alsharef Farah 66 Dr. Ahmed Alsharef Farah 67 Axial CT of maxillary sinuses. Sphenoid sinuses:

• Sphenoid sinuses are normally paired and occupy the body of the sphenoid bone just below the sella turcica.

Dr. Ahmed Alsharef Farah 68 Dr. Ahmed Alsharef Farah 69 Sagittal, T1-weighted MRI of sphenoid sinus. Dr. AhmedCoronal, Alsharef T 1Farah-weighted MRI of sphenoid sinuses. 70 Dr. Ahmed Alsharef Farah 71 Coronal CT of sphenoid sinuses. Frontal sinuses:

• The frontal sinuses are located within the vertical portion of the frontal bone. • These sinuses are typically paired and are separated along the sagittal plane by a septum. • The frontal sinuses are rarely symmetric, vary greatly in size.

Dr. Ahmed Alsharef Farah 72 Dr. Ahmed Alsharef Farah 73 Coronal CT of frontal sinuses. The End

Dr. Ahmed Alsharef Farah 74