Norma Frontalis

Norma Frontalis

• The anterior view of the skull.

• Presents an irregular surface with 3 excavations:

1. one nasal cavity2. two orbital cavities.

Six Regions of Norma Frontalis• Frontal Region• Orbital Region• Nasal Region• Zygomatic Region• Maxillary Region• Mandibular Region.

I. THE FRONTAL REGION

Boundaries:

Superior - top of the skull

Inferior - orbits and root of the nose - frontal process of the maxillae

Laterally - frontal process of the

zygomatic bone.

Characteristics Features:1. Frontal Tuberosity or

Eminence2. Superciliary Arch3. Glabella4. Nasion5. Supraorbital Margin6. Supraorbital Notch.

II. THE ORBITAL REGION

Bones involved:

1. Maxilla2. Zygomatic Bone3. Sphenoid Bone4. Frontal Bone5. Palatine Bone6. Ethmoid Bone7. Lacrimal Bone.

BOUNDARIES OF THE

ORBITAL CAVITY

Roof

- orbital plate of the frontal bone

- lesser wings of sphenoid.

Lateral wall

- Zygomatic process of the frontal bone

- Orbital plate of the zygomatic bone

- Orbital plate of the greater wings of sphenoid.

Medial Wall

- Frontal process of the maxilla

- Lacrimal bone

- Orbital plate of ethmoid bone

- Body of sphenoid.

Floor

- Orbital plate of the maxilla

- Orbital plate of the zygomatic bone

- Orbital process of the palatine bone.

Base

Superiorly – frontal bone

Medially - frontal process of the maxilla

Laterally - frontal process of the zygomatic

bone

Inferiorly - Maxilla medially - zygomatic bone laterally.

Apex

- Formed by the convergence of the four walls.

OPENINGS INTO THE

ORBITAL CAVITY

Opening Location Structure

Orbital opening

5/6 of the eyeball

Supraorbital notch / foramen

Superior margin

Supraorbital nerves/vessels

Infraorbital groove and canal

Floor/orbital plate of maxilla

Infraorbital nerve and blood vessels

Nasolacrimal canal

Medial wall Nasolacrimal duct

Opening Location Structure

Inferior Orbital Fissure

Between maxilla and greater wing of sphenoid

1. Maxillary nerve and its zygomatic branch

2. Inferior Opthalmic vein

3. Sympathetic nerves

Opening Location StructureSuperior Orbital Fissure

Between greater and lesser wings of sphenoid

1. Lacrimal N.2. Frontal N. 3. Trochlear N.4. Occulomotor

N. (upper and lower divisions)

5. Abducent N.6. Superior

Opthalmic Vein

Opening Location Structure

Anterior Ethmoidal Foramen

Frontal Bone 1. Nasociliary N.

2. Anterior Ethmoidal V. A. and N.

PosteriorEthmoidal Foramen

Frontal Bone 1. Posterior Ethmoidal V., A. and N.

Optic Canal Lesser Wing of Sphenoid

1. Optic N.2. Opthalmic

N.

III. THE NASAL REGION

Bones involved

1. Nasal Bone2. Frontal Bone3. Ethmoid Bone4. Sphenoid Bone5. Vomer6. Maxilla7. Palatine Bone8. Lacrimal Bone9. Inferior nasal Concha.

BOUNDARIES OF THE

NASAL CAVITY

Anterior – pyriform aperture

Posterior - Pharynx thru the posterior nares.

Superior Wall

1. Anterior – nasal bone -nasal process of the frontal bone

2. Middle- cribriform plate of ethmoid bone

3. Posterior- body of the sphenoid

Median Wall

- Perpendicular plate of ethmoid

- Vomer.

Lateral Wall

1. Contain turbinates or conchae which are bony elevations made up of:

a. Superior and middle conchae of the ethmoid boneb. Inferior nasal conchae or turbinates

2. Bounded by the posterior nares3. Contain meatuses between nasal conchaes.

The Paranasal Sinuses

These are pneumatic bones surrounding the nasal cavity.

Functions:1. Lighten the bone of the skull2. Resonating chambers.

Meatuses and Sinus Drainage of the Lateral Wall of the Nasal Cavity

Meatus Sinus Drainage

Supreme or highest nasal meatus or spheno-ethmoidal recess

Sphenoidal sinus

Superior Nasal Meatus

Posterior ethmoidal sinus

Meatuses and Sinus Drainage of the Lateral Wall of the Nasal Cavity

Meatus Sinus Drainage

Middle nasal meatus Anterior and middle ethmoidal sinus; frontal sinus; and maxillary sinus

Inferior nasal meatus Nasolacrimal duct

IV. THE ZYGOMATIC REGION

- forms the prominence of a cheek, contributes to the lateral orbital wall and floor, parts of the walls of temporal and infratemporal fossae and completes the zygomatic arch.

- roughly quadrangular with anteromedial and frontal processes.

- It can be described as having three surfaces, five borders and two processes.

Lateral View of the Zygomatic Bone

The Three Processes of the Zygomatic Bone:

1. Temporal process

2. Frontal process

3. Maxillary process

THE THREE SURFACES OF THE ZYGOMATIC BONE

1. Anterolateral Surface

-is convex and pierced near its orbital border by the zygomaticofacial foramen (for the zygomaticofacial nerve and vessels); below this zygomaticus minor and, posteriorly, zygomaticus major are attached.

2. Posteromedial Temporal Surface

- has a rough anterior area for articulation with the maxilla and a smooth, concave posterior area extending up posteriorly on its frontal process as the anterior aspect of the temporal fossa.

3. Orbital Surface

- smooth and concave, is the anterolateral part of the orbital floor and adjoining lateral wall, extending up on the medial aspect of its frontal process.

THE FIVE BORDERS OF THE ZYGOMATIC BONE

1. Orbital2. Maxillary3. Temporal4. Posteroinferior5. Posteromedial

OPENINGS OF THE ZYGOMATIC REGION

Foramen Location Structure

Zycomatico-facial foramen

Below the lateral part of the lower margin of the orbit

1. zygomatigo-facial branch of the Zygomatic N.

2. Lacrimal A.

Zygomatico-temporal foramen

Temporal process of the zygomatic bone

Zygomatico-temporal N. and blood vessels

V. MAXILLARY REGION

Characteristic Features:

1. Anterior nasal spine2. Infraorbital foramen3. Canine fossa4. Subnasal/incisive fossae5. Canine emminence6. Jugum or zygomatico-

alveolar arch7. Alveolar processes of the

maxilla.

Lateral View of the Maxilla

The 4 processes:1. Frontal process2. Zygomatic

process3. Alveolar process4. Palatine process.

OPENINGS OF THE MAXILLA IN NORMA FRONTALIS

Opening Location Structure

Infraorbital foramen

Below the infraorbital margin

Infraorbital N., A., and V.

Alveolar processes

Lower margin of the maxilla

Roots of maxillary teeth

VI. THE MANDIBULAR REGION

- Involves the mandible which is the strongest bone of the face

- Houses the lower teeth- Develops in 2 symmetrical halves which fuse

and ossify in the first year of life.

Characteristic Features of the Mandible

1. Symphisis menti2. Mental protruberance3. Alveolar processes4. Mental foramen.

OPENINGS IN THE

MANDIBLE

rOpening Location Structure

Mental foramen Between the apices of the mandibular premolars

Mental nerve

Alveolar processes

Upper border of the mandible

Roots of mandibular teeth

Mandibular foramen

Lingual side of the ramus of the mandible

Mandibular N.