Intra-Oral and Extra-Oral Anatomy

Question 1

What are the extra-oral surfaces visible anteriorly

Answer 1

Frontal Region - forehead
Orbital Region -
Parotid Region – just infront of the ear
Buccal Region – the cheek area
Mental Region – the region around the chin
Oral Region – the region of the mouth
Nasal Region – the region around the nose.

Question 2

What extra-oral surfaces does the lateral view show of the head?

Answer 2

Frontal Region - forehead
Orbital Region -
Parotid Region – just infront of the ear
Buccal Region – the cheek area
Mental Region – the region around the chin
Oral Region – the region of the mouth
Nasal Region – the region around the nose.
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Parietal Region – covering the parietal bone
Temporal Region
Zygomatic Region – cheek bone region, cheek bone also known as zygomatic bonme
Auricular Region – around the ear
Occipital Region – located posteriorly, on the scalp
Infra-orbital Region – just below the eyes

Question 3

What is the structure of facial skin?

Answer 3

Elastic
Vascular
Rich in sebaceous glands and sweat glands
Little deep fascia
The muscles of facial expression are found in the superficial fascia
Mainly on bone or fascia and insert onto skin.

Question 4

How does facial skin innervation work?

Answer 4

Lots of cutaneous branches that travel through the superficial fascia to supply sensitive innovation to the skin.

Sensory innovation of skin comes from trigeminal nerve, with it’s subsections supplying specific facial regions.

Question 5

What does the different divisions of the trigeminal nerve supply?

Answer 5

The ophthalmic division of trigeminal nerve CN V1 supplies upper region of face including the upper eyelids, down the root of the nose, over the bridge of the nose to the tip of the nose.
The maxillary division of the trigeminal nerve, CN V2 supplies mid region of face, lower eyelids, upper lips and the wings of the nose.
The mandibular division of the trigeminal nerve, CN V3, supplies the lower face including the lower lip and some anterior aspects of the auricle.

Question 6

What are the muscles of facial expression, what are they responsible for and what are they innervated by?

Answer 6

Responsible for Facial Expression
All innervated by CNVII – facial nerve

Frontalis
Orbicularis Oculi
Quadratus Superioris
Orbicular Oris
Platysma

Question 7

What is a fat pad important for and where is it located?

Answer 7

Within cheek region, a fat pad important for suckling, for example in infants, exists.
The buccal fat pad pevents the cheeks from collapsing in a little.

Question 8

What occurs at zygomatic bones?

Answer 8

Zygomatic bones, also known as cheek bones are where the zygomatic muscles attach to the zygomatic minor and major.

Question 9

What is the function of the vermillion border?

Answer 9

Vermillion border runs around the outside of the lips and separates the mucous membrane layer of the lips from the skin surrounding the lips. - important aesthetically, trauma may require surgery for repair.

Wrinkles form at 90 degrees to muscle fibre direction.

Question 10

Where are muscles of mastication found?

Answer 10

Mainly found in posterior part of face around ramus of mandible and TMJ

Question 11

Where are the muscles of facial expression mainly found?

Answer 11

Muscles of facial expression are mainly found in anterior part of face around sphincters

Question 12

What are the muscles of mastication?

Answer 12

Temporalis - found in the temporal region
Masseter – easy to palpate, important landmark for facial vein and artery crossing

Lateral Pterygoid
Medial Pterygoid – mirror image of the masseter
Both are attached to the pterygoid plates of the sphenoid bone
All innervated by CV V3 – mandibular division of the trigeminal nerve

Question 13

What are the three pairs of major salivary glands?

Answer 13

Three pairs of major salivary glands.
Right and Left Parotid glands – Superficial to masseter
Parotid duct drains the parotid gland, passes horizontally to penetrate the buccal fat pad and pierces through the cheek muscle to empty opposite the upper second molar tooth.

Submandibular glands, containing a superficial part and a deep part, contains a submandibular duct which empties in the floor of the mouth.

Sublingual gland located in the floor of the mouth, with numerous openings into the floor of the mouth.

Question 14

How is blood supplied to the face? What are the other external carotid branches?

Answer 14

Arterial blood supply is supplied by facial artery, which is a branch of external carotid.
External carotid branches:
Superficial temporal
Maxillary
Inferior alveolar artery
Facial
Lingual
Superior Thyroid
Ascending Pharyngeal
Posterior Auricular
Occipital

Question 15

How is blood drained from the face? (venous drainage)

Answer 15

Occurs via the facial vein
Runs along the facial artery
Blood drains into internal jugular vein which will continue to the venous angles

Question 16

What are the superficial structures involved in lymphatic drainage?

Answer 16

Superficial ring of regional lymph nodes.
(drain lymph from scalp, face, superficial upper neck)
Located at the junction of the head and neck
Most important lymph nodes are:
Submental – draining lower lip and tip of tongue
Submandibular
Parotid
Mastoid
Occipital

Question 17

What are the regions that are part of the paranasal sinuses and what do they do?

Answer 17

Frontal Sinus
Ethmoidal Cells
Maxillar Sinuses
Sphenoidal Sinus

They produce a lot of mucus that drains from all of the different sinuses into the nasal cavity

Question 18

What are mucous membranes?

Answer 18

Mucous membrane lined, air filled spaces within the skull, divided into parts

Question 19

What is the bony orbit formed by?

Answer 19

Bony orbit – formed from seven bones, frontal, zygomatic, maxilla, nasal, lacrimal bone, ethnoid bone, sphenoid bone

The size of the bony orbit is larger than the eyeball, the area between the eyeball and bony orbit contains fatty tissue.

Question 20

What is the external layer of the eyelid called?

Answer 20

The external layer of the eyelid is called Orbicularis Oculi, has two parts:
Circular part which encircles the bony orbit
The palpebral part which contributes to the eyelids.
Palpebral part is for gentle closing of the eyelids
Circular part is responsible for tight closing of eyes.

Question 21

What does the eye consist of?

Answer 21

Sphincter muscle,
Palpebral fissure which is the eye opening.
The upper and lower eye lids join medially and laterally, in areas known as the medial and lateral canthus
White of the eyeball is known as the sclera
Sclera is covered by a clear structure known as conjuctiva
Iris
Pupil

Question 22

What is the function of lacrimal glands?

Answer 22

Lacrimal glands produces lacrimal fluid (tears) which descends inferiorly, washes over the eye, pushes to the medial angle of the eye, drains through the lacrimal puncta which are tiny holes, to the lacrimal sac and eventually reaches nasal cavity through the nasolacrimal duct.

Overflow of tears results in external expulsion of tears through the side of eyes or nasally.

Question 23

What is the surface anatomy of the mouth?

Answer 23

The Main structure in lower part of the face, surrounded by orbicularis oris.
The mouth has an upper lip and lower lip, which is surrounded by a vermilion border.
The lips meet at medial aspects at the commissure.
Fissure is the line between the lips
Philtrum is the vertical groove in the midline of the area above the upper lips.

Question 24

What is the characteristics of the TMJ

Answer 24

You can palpate it’s location when the jaw opens or closes.
TMJ is formed by the articulation of the condylar head of the mandible and the Glenoid fossa of the temporal bone of the cranium.

Question 25

What are the surface anatomy features of the mouth?

Answer 25

Dorsum of the Tongue
○ Hard Palate
○ Soft Palate
○ Upper Dental Arch
○ Lower Dental Arch
○ Gingiva
○ Posterior wall of the oropharynx
○ Uvula
○ Arches of the soft Palate (skeletal muscles covered in mucosa):
○ Palatopharyngeal arch
○ Palatoglossal Arch
Palatine Tonsil - between the two arches of the soft palate

Question 26

What are the two boundaries to the Oral cavity?