A detailed description of the bones of the face, their articulations and special features they posses. Also mentioned are structures that run through these bones like nerves, and muscular attachments.

1. ANATOMY OFTHE
OROFACIAL
SKELETON
Aboagye Kofi Nti Baffour

2. Outline
■ Overview
■ Development of the orofacial skeleton
■ Maxillae
■ Zygomatic bones
■ The Orbit
■ Nasal bones
■ Lacrimal bones
■ Palatine bones
■ Inferior nasal conchae
■ Vomer
■ Mandible
■ References

3. Overview
■ The skull contains 22 bones.The cranium has 8 bones.
■ The skeleton of the face consists of 14 bones.
■ These are the unpaired mandible and vomer, and the paired
maxillae, zygomatic bones, nasal bones, lacrimal bones, palatine
bones, and inferior nasal conchae.
■ These bones, together with certain cranial bones (frontal bone and
portions of the ethmoid and temporal bones), form the face.
■ Facial bones give shape and individuality to the face.
■ They also support the teeth and provide attachments for various
muscles that move the jaw and cause facial expressions.

4. Overview cont’d
An anterior and a posterior view of a frontal (coronal) section of the skull.

5. Development of the orofacial skeleton
■ The formation of the skull begins during the fourth week of embryonic
development and continues well beyond the birth of the baby.
■ Three aspects of the embryonic skull are involved in this process: the
chondrocranium, the neurocranium, and the viscerocranium.
■ The chondrocranium undergoes endochondral ossification to form the bones
supporting the brain.
■ The neurocranium develops through membranous ossification to form the bones
covering the brain and facial region.
■ The viscerocranium (splanchnocranium) develops from the embryonic visceral
arches to form the mandible, auditory ossicles, the hyoid bone, and specific
processes of the skull.

6. Development cont’d

7. The maxillae
■ The paired maxillary bones, or maxillae form the upper jaw and the central part of the face.
■ They are considered the keystone bones of the face because they articulate with all other facial
bones except the mandible.
■ The maxillae have an alveolar margin that contains teeth in alveoli.
■ The palatine processes project medially from the alveolar margins to form the anterior region of
the hard palate, or bony roof of the mouth.
■ The frontal processes extend superiorly to reach the frontal bone, forming part of the lateral
aspect of the bridge of the nose.
■ The maxillae articulate laterally with the zygomatic bones at the zygomatic processes and
medially with with the nasal bones.
■ The maxillae contain the maxillary sinuses, which are the largest of the paranasal air sinuses,
extend from the orbit down to the roots of the upper teeth.
■ The maxilla, along with several other bones, forms the borders of the inferior orbital fissure in
the floor of the orbit.
■ The infraorbital nerve proceeds anteriorly to enter the face through the infraorbital foramen.

8. The maxillae cont’d

9. The zygomatic bones
■ The paired zygomatic bones are commonly called the
cheekbones (zygoma=cheekbone).
■ They are irregularly shaped.
■ Articulations of the zygomatic bones include:
– The zygomatic process of a temporal bone posteriorly
– The zygomatic process of the frontal bone superiorly
– The zygomatic process of the maxilla anteriorly
■ The zygomatic bones form the prominences of the cheeks
■ They also form part of the margin of each orbit.

10. The zygomatic bones cont’d
The lateral view of the zygomatic bone

11. The orbit

12. The nasal bones
■ There are 2 nasal bones
■ They rectangular in shape
■ The 2 nasal bones join medially to form the bridge of the nose.
■ Articulations include
 Medially – the contralateral nasal bone.
 Laterally – the maxillae.
 Superiorly – the frontal bone.
 Posteriorly – the perpendicular plate of the ethmoid bone.
 Inferiorly – the cartilages that form most of the skeleton of the
external nose.

13. The nasal bones cont’d
Anterior view of the nasal bones

14. The lacrimal bones
■ Lacrima = tear
■ The delicate, fingernail-shaped lacrimal bones are located in the medial
orbital walls.
■ They articulate with the:
– Frontal bone superiorly,
– The ethmoid bone posteriorly,
– The maxilla anteriorly.
■ Each lacrimal bone contains a deep groove that contributes to a lacrimal
fossa.
■ This fossa contains a lacrimal sac that gathers tears, allowing the fluid
to drain from the eye surface into the nasal cavity.

15. Lacrimal bone cont’d

16. The palatine bones
■ The paired palatine bones lie posterior to the maxillae.
■ They are L-shaped bones.
■ They articulate with each other at their inferior horizontal plates.
■ They complete the posterior part of the hard palate.
■ The perpendicular plates form the posterior part of the lateral walls of the
nasal cavity and also form a small part of the orbits.
■ At the posterior angle of the hard palate is the large greater palatine
foramen that provides passage for the greater palatine nerve and
descending palatine vessels.
■ Two or more smaller lesser palatine foramina are positioned posterior to
the greater palatine foramen.
■ Branches of the lesser palatine nerve pass through these openings.

17. The palatine bones cont’d

18. The inferior nasal conchae
■ The paired inferior nasal conchae are thin, curved bones in
the nasal cavity.
■ They projecting medially from the lateral walls of the nasal
cavity, and lie inferior to the middle nasal conchae of the
ethmoid bone.
■ They are the largest of the three pairs of conchae.

19. The inferior nasal conchae cont’d

20. The vomer
■ Vomer means plowshare.
■ The slender, plow-shaped vomer lies in the nasal cavity,
where it forms the inferior part of the nasal septum.
■ Along with the perpendicular plate of the ethmoid bone, it
supports the layer of septal cartilage that forms most of the
anterior and inferior parts of the nasal septum.

21. The vomer cont’d

22. The mandible
■ The U-shaped mandible is the largest, strongest bone in the
face.
■ It has a horizontal body that forms the inferior jawline, and two
upright rami, and a base, or lower border.
■ Each ramus meets the body posteriorly at a mandibular angle.
■ At the superior margin of each ramus are two processes.
■ The anterior coronoid process is a flat, triangular projection.The
temporalis muscle inserts here.
■ The posterior process enlarges superiorly to form the
mandibular condyle. It articulates with the temporal bone to
form the temporomandibular joint.

23. The mandible cont’d
■ The coronoid and condylar processes are separated by the mandibular
notch.
■ Its superior border is the alveolar margin which contains the teeth.
■ Anteriorly, the fusion between the two halves of the mandible is called
the mental protuberance.
■ On the medial surface of each ramus is a mandibular foramen through
which the inferior alveolar nerve enters the mandibular body and
supplies the roots of the lower teeth.
■ In front of the foramen is a projection of bone, called the lingula, for the
attachment of the sphenomandibular ligament.
■ The mental foramen, which opens on the anterolateral side of the
mandibular body, transmits blood vessels and nerves to the lower lip
and the skin of the chin.

24. The mandible cont’d
■ The genial tubercles are located on the medial surface of the body
of the mandible in the median plane.These give origin to the
genioglossus muscles above and the geniohyoid muscles below.
■ The digastric fossa lies below the genial tubercles.The anterior
bellies of the digastric muscles attach there.
■ The mylohyoid line can be seen as an oblique ridge that runs
backward and laterally from the area of the genial tubercles to an
area below and behind the third molar tooth.
■ The submandibular fossa lies below the posterior part of the
mylohyoid line.
■ The sublingual fossa lies above the anterior part of the mylohyoid
line.

25. The mandible cont’d

26. The mandible cont’d

27. The mandible cont’d

28. References
■ Van De Graaff: Human Anatomy, Sixth Edition
■ Marieb: Human Anatomy, Sixth Edition
■ Snell:ClinicalAnatomy By Regions, Ninth Edition