Radiographic Anatomy of the Skull Dr. Meghan Woodland November 25, 2010

Radiographic Anatomy Radiographic Anatomy of the Skullof the Skull

Dr. Meghan Woodland

November 25, 2010.

Patient Preparation:

• Radiographs should be taken under general anaesthesia– In critical cases, lateral and VD views can be

obtained with minimal sedation

• Standard skull series:– Lateral– VD

• Nasal, Bulla and Dental series: various oblique and open-mouth views.

Typical Radiographic View

1. Open mouth VD

Direction of X-rays

Joe P. Morgan

This view is used to evaluate the nasal cavity, which is important in animals with nasal discharge.

Note the increased opacity in the left nasal passage

Typical Radiographic View

2. Lateral View

Joe P. Morgan

Can be used to evaluate for nasal or frontal bone fractures in trauma patients

Radiograph is oblique as the dog was awake and difficult to keep still.

Typical Radiographic View

3. Frontal Sinus View

Direction of X-rays

X-ray film

Joe P. Morgan

Important for evaluating for the presence of sinusitis in patients with nasal discharge.

Note the increased opacity within the left frontal sinus

Normal Appearance DV/VD

Frontal Bone & Sinus

Zygomatic Arch

Maxillary Bone

Mandible

Tympanic Bullae

Horizontal Ear Canal

Note the decreased amount of air within the right ear canal.

Note the mineralization of both ear canals

Temporomandibular Joint

Normal Appearance Lateral

Mandible

Mandibular symphyseal fracture

Maxillary Bone

Zygomatic Bone

Orbital Margin

Normal cat bulla on lateral or oblique view

Coronoid Process of the Mandible

Temporomandibular Joint

Condylar Process of Mandible

Retroarticular Process

Angular Process of the Mandible

Close up of Skull

TMJ Joint

Condylar Process

Retroarticular Process

Angular Process

Normal Appearance Open Mouth VD

Ethmoid Turbinates

Maxillary Turbinates

Turbinates• Turbinate pattern changes at the level of PM3. • Maxillary turbinates have a linear pattern

• Ethmoid turbinates have a more coarse pattern

Vomer Bone

Vomer bone

Nasal Septum

Palatine Fissure

Open Mouth VD and CT

• Compare• 1. Radiograph

on the left• 2. CT images

on the right

• Note the turbinate patterns at the different levels

Normal Appearance Frontal Sinus View

Normal Appearance Lateral View

Frontal Sinus

Ethmoid Turbinates

Nasal Turbinates

Nasopharynx

Maxillary Recess

Tooth Root Abscess

Normal Dental Formula(Canine)

• Maxillary teeth• 3 (x2) Incisors• 1 (x2) Canine • 4 (x2) Premolars• 2 (x2) Molars

Normal Dental Formula(Canine)

• Mandibular teeth• 3 (x2) Incisors• 1 (x2) Canine • 4 (x2) Premolars• 3 (x2) Molars

Normal Dental Formula(Feline)

• Maxillary teeth• 3 (x2) Incisors• 1 (x2) Canine • 3 (x2) Premolars• 1 (x2) Molars

Normal Dental Formula(Feline)

• Mandibular teeth• 3 (x2) incisors• 1 (x2) canine • 2 (x2) Premolars• 1 (x2) Molars

Deciduous Teeth

• Time of Replacement• Incisors 3-5

months• Canines 5-7

months• Premolars 5-6

months

Deciduous Teeth

Deciduous Teeth

Deciduousteeth

Permanent teethPermanent teeth

Normal Teeth: Age Related Changes

• As an animal ages the teeth will:• have a decreased pulp cavity• closure of the apical foramen• regression of alveolar crest• sclerosis of alveolar bone

Age Related Changes• As an animal ages the teeth will:

• have a decreased pulp cavity• closure of the apical foramen• regression of alveolar crest• sclerosis of alveolar bone

Age Related Changes• As an animal ages the teeth will:

• have a decreased pulp cavity• closure of the apical foramen• regression of alveolar crest• sclerosis of alveolar bone

Age Related Changes• As an animal ages the teeth will:

• have a decreased pulp cavity• closure of the apical foramen• regression of alveolar crest• sclerosis of alveolar bone

Age Related Changes

Increasing Age

Age Related Changes

Note the decreasedsize of pulp cavity

Normal Tooth Structure

Normal Tooth StructureCrown - covered with enamel and above gum line

Normal Tooth StructureRoot - below gum line surrounded by bone

Normal Tooth Structure

Pulp Cavity - contain blood vessels and nerves radiolucent zone in center to tooth

Normal Tooth Structure

Periodontal Membrane - radiolucent (black) line surrounding the tooth root

Normal Tooth StructureLamina dura - sclerotic (white) line just outside the periodontal ligament

The End