Facial Bones

·      14 facial bones:

o   2 Maxilla

o   Mandible

o   2 Conchae

o   2 Nasal

o   Vomer

o   2 Lacrimal

o   2 Zygomatic

o   2 Palatine

·      Nasal Bones: make up the bridge of the nose (nasion externally)

o   Articulate with – frontal, ethmoid, maxilla

·      Lacrimal bones: posterior to the nasal bones, on the medial wall of each orbit

o   Lacrimal groove: junction between lacrimal bone and maxilla bone

§  Accommodates lacrimal sacs – drain excess lacrimal fluid

·      Palatine bones: L-shaped, posterior to nasal cavity, between the maxilla and pterygoid process

o   Horizontal portion: joins with the maxilla palatine process to make up the posterior aspect of the hard palate

o   Vertical portion: extend upwards to form the lateral wall of the nasal cavity and medial wall of the orbit

·      Maxillary bones: largest immovable facial bones, makes up a large part of the centre of the face

o   Anterior nasal spine: maxillary bones fuse at the midline underneath the nasal cavity, to form this – correlates to the Acanthion external landmark

o   Infraorbital foramen: located at the bottom of each orbit, it’s the passage for the infraorbital nerve + blood vessels

o   Maxillary sinuses: large sinuses located inferior to the orbits

o   Maxillary bones contain 4 processes:

§  Frontal: the section that surrounds the nasal bones, on the medial and lateral sides

§  Zygomatic: the arch from the teeth to underneath the zygomatic bone

§  Alveolar: directly above the teeth, receives their roots + nerves

§  Palatine: forms the largest section (3/4) of the hard palate, extending posteriorly from the alveolar process

·      Why is the hard palate important in medical imaging?

When performing foetal scans, you need to ensure the hard palate is forming correctly – abnormalities can be common, and also often cause deformation of the upper lip; which would need to be fixed post-birth through surgery.

·      Zygomatic bones (zygoma): creates the cheek bones + part of the lateral side of orbits

o   Articulates with the maxilla, temporal, frontal, and sphenoid bones

o   Temporal process: extends posteriorly to join the zygomatic process of the temporal bone

§  Forms the zygomatic arch

o   Frontal process: where the zygomatic bone connects with the frontal bone

·      Inferior nasal conchae bones: arise from the maxillary bone, has a scroll-like appearance

o   They work in conjunction with the superior and middle nasal concha of the ethmoid bone

§  These divide the nasal cavity into 3 openings – meati/meatus

·      Vomer bone: unpaired facial bone located on the midsagittal line, that completes the bony nasal septum

o   Is the bottom/inferior portion of the nasal septum

o   Projects superiority (upwards) to join with the perpendicular plate of the ethmoid bone

·      Mandible bone: the largest movable facial bone, makes up the jaw

o   Horizontal portion (Body): curved, contains the alveolar process + mental foramina

§  Alveolar process: runs underneath the teeth, houses its roots and nerves

§  Mental foramina: 2 on either side of the jaw, superior and inferior to each other – allows the passage of the mental artery + nerve

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o   Vertical portion (Ramus): contains 2 process at the top, coronoid + condyloid

§  Coronoid process: anterior process, serves as an attachment site for the temporalis + masseter muscles

§  Condyloid process (Condyle): posterior process, articulates with the mandibular fossa of the temporal bone to form TMJ

§  Mandibular notch: the concave surface between the coronoid process + condyloid process

§  Angle of mandible: forms the external landmark gonion

§  Symphysis: chin bone