1751 Facial Bones Anatomy

What are the 14 Facial Bones

• 2 Nasal

• 2 Maxillary (Maxilla Singular)

• 2 Lacrimal

• 2 Zygomatic

• 2 Palatines

• 2 Inferior Nasal Conchae

• Vomer

• Mandible

• (The 2 palatines and vomer are located internally and are not visible on a skeleton from the exterior. Facial bones contribute to the shape and formation of a person’s face)

What do facial bones provide

Structure, shape and support for the face. They form a protective housing for the upper ends of the respiratory and digestive tracts

Maxilla (2)

• Largest immovable bones of face

• Articulated with all other facial bones, except mandible

• Each maxilla assists in formation of 3 cavities of the face: roof of the mouth, nasal cavity, and part of floor of orbit

• 4 processes (frontal, zygomatic, alveolar, palatine)

• All other facial bones are closely associated with the 2 maxillae; thus they are structurally the most important bones of the upper face

Zygomatic Bones (2)

• Prominence of cheeks

• Forms part of side wall and floor of orbital cavities

• Temporal Process unites with zygomatic process of temporal bone to form the zygomatic arch

• Zygomatic arch is the cheek bone

What bones do the zygomatic bones articulate with

• Frontal bone superiorly

• Temporal bone side

• Maxilla anteriorly

• Sphenoid posteriorly

Tripod (Trimalar) Avulsion Fracture

• Fracture of lateral wall

• Results in a free floating zygoma

• Caused by a blow to the cheek

• Fracture in 3 places

  • Zygomatic bone - frontal process

  • The maxilla - Zygomatic process

  • The Temporal Bone - Zygomatic Process

Lacrimal (2)

• Smallest bones in the skull

• About the size of a fingernail

• Lie anteriorly and medially within orbit

• Posterior to frontal processes of maxilla

• Each bone contains a lacrimal foramen through which the tear duct passes

• Both lacrimal and nasal bones articulate with 2 cranial bones and 2 facial bones

What bones do the lacrimal bones articulate with

• Frontal Bone

• Ethmoid Bone

• Maxilla

• Inferior Nasal Conchae

Nasal Bones (2)

• Small and thin

• Vary in size

• 2 join together at the MSP to form bridge of nose

• Point of junction of 2 nasal bones with frontal bone - nasion

• Most commonly fractured facial bone

What bones do the nasal bones articulate with

• Other nasal bone

• Frontal bone

• Ethmoid bone

• Maxillae

Inferior Nasal Conchae

• Long narrow very thin bones with a lateral curl

  • Gives scroll like appearance

• Upper 2 nasal conchae are processes of ethmoid bone. The inferior is a separate bone

• The 3 nasal conchae are covered with a mucous membrane to warm, moisten and clean inhaled air

• The purpose of the 3 pairs of nasal conchae are to divide the nasal cavity into various compartments. These compartment break up the flow of air coming into the nasal cavities before it reaches the lungs. The air is warmed and cleaned

Palatine Bones

• 2 L shaped bones

• Vertical portion lies between the pterygoid process of sphenoid and maxilla

• Horizontal portion fuses with palatine process of maxilla to complete bony palate

• Composed of vertical and horizontal plates

• Located internally and are not visible from the outside

The maxilla palatine processes to form the hard palate. Separation of the 2 causes cleft palate

Vomer Definition

Plowshare due to the resemblance to the shape of a plow cutting blade

Vomer Bone

• Thin plate of bone

• In the MSP of the nasal cavity

• Forms inferior portion of nasal septum

• The surface of the vomer are marked by small furrow-like depressions for blood vessels, thus the source of nosebleed with trauma to the nasal area

• Deviated septum describes the clinical condition wherein the nasal septum is deflected or displaced laterally from the midline of the nose. This deviation usually occurs between the septal cartilage and the vomer

Mandible

• Largest and densest facial bone

Body of Mandible

Curved horizontal portion

Rami of Mandible

2 vertical portions on each side of body

Angle of mandible (Gonion)

Junction of body and ramus

Mental Protuberance of Mandible

Anterior, triangular prominence

Symphysis of Mandible

Most anterior and centra part where left and right halves fuse

Alveolar Portion of Mandible

Superior border of body; consists of spongy bone that supports roots of teeth

Mental Foramina of Mandible

Small openings on each side below the second premolar; transmit nerves and blood vessels

Coronoid Process of Mandible

Anterior process on top of ramus

Condylar Process of Mandible

Posterior process on top of ramus

Mandibular Notch

Concave area at top of ramus between coronoid and condylar process

Mandible and TMJ

• Mandible is the only moveable bone on adult skull

• TMJ only moveable joint in skull

  • Formed by the condyle (head) of condyloid process

  • Fits into the temporomandibular fossa of temporal bone

  • Slants posteriorly 15 degrees and inferiorly/medially 15 degrees

• Just anterior to and slightly superior to the EAM

Hyoid Bone

• Small U-Shaped bone situated at the base of the tongue

• Accessory bone of axial skeleton - not a facial or cranial bone

• Only bone in the body that does not articulate with another bone

• Held in position by the ligaments extending from the styloid process of the temporal bone

• Hyoid serves as an attachment for certain muscles of the larynx and tongue and is easily palpated just above the larynx

What bones compose the Orbits (7 each, 14 total)

• 3 Cranial Bones

  • Frontal

  • Sphenoid

  • Ethmoid

• 4 Facial Bones

  • Maxilla

  • Zygoma

  • Lacrimal

  • Palatine

Orbits

• Cone shaped

• Rim is base

• Apex is posterior portion of cone and corresponds to the optic foramen (opening for optic nerve)

• Using OML parallel to floor, orbits will project upward 30 degrees and toward MSP 37 degrees

• Each orbit contains 3 openings in the posterior portion

  • Superior orbital fissure

  • Inferior orbital fissure

  • Optic Foramen - For transmission of optic nerve which is a continuation of the retina

• Each orbit has the 3 openings for 12 pairs of cranial nerves to pass

Blow Out Fracture

• Results from a direct blow to the front of the orbit that transfers the force to the orbital walls and floor (orbital floor just above maxillary sinuses)

• Tissue - FIbrous

• Type - Suture

• Movement - Immovable

• Coronal Suture

• Sagittal Suture

• Lambdoidal Suture

• Squamosal Suture

• Tissue - Synovial

• Type - Hinge and Gliding

• Movement - Freely Moveable

Temporomandibular

• Tissue - FIbrous

• Type - Gomphosis

• Movement - Immovable

Alveolar Sockets

• Tissue - Synovial

• Type - Ellipsoidal

• Movement - Freely Moveable

Atlantooccipital

Basal Fracture

Fracture located at the base of the skull

Blowout Fracture

Fracture of the floor of the orbit

Contre-Coup Fracture

Fracture to one side of a structure caused by trauma to the other side

Depressed Fracture

Fracture causing a portion of the skull to be pushed into the cranial cavity

Le Fort Fracture

Bilateral horizontal fracture of the maxillae

Linear Fracture

Irregular or jagged fracture of the skull

Tripod Fracture

Fracture of the zygomatic arch and orbital floor rim and dislocation of frontozygomatic suture