Anatomy of the head and neck 2

Question 1

What does the oral cavity include?

Answer 1

• The oral cavity is the first part of the digestive tract, it includes the lips, the lining inside the cheeks and lips, the front 2/3rds of the tongue, the upper and lower gums, the floor of the mouth under the tongue, the bony roof of the mouth

Question 2

What does the palate form?

What are the 2 parts of the palate?

Answer 2

• The palate (also known as the ‘roof of the mouth’), forms a division between the nasal and oral cavities. It is separated into two distinct parts:
• Hard palate – comprised of bone.
o It is immobile.
• Soft palate – comprised of muscle fibres covered by a mucous membrane.
• It can be elevated to close the pharyngeal isthmus during swallowing – this prevents the food bolus from entering the nasopharynx.

Question 3

What are the 3 divisions of the oral cavity?

Answer 3

1. Oral Vestibule: Space between teeth and lips
2. Oral Cavity Proper: Space inside teeth and gums
3. Oropharynx: Continuous with oral cavity

Question 4

What are the arches in the oral cavity called and function to do?

Answer 4

The arches represent projections from their muscles:
• PALATOPHARYNGEAL MUSCLE
• PALATOGLOSSUS MUSCLE
These muscles are involved in tongue movements and are covered in a mucus tissue
The palatopharyngeal arch at the back of the mouth signs the link between the oral cavity and the pharynx

Question 5

What is the uvula?

Answer 5

The uvula is a portion of the softy palate that projects back and inferiorly and moves in a posterior direction while swallowing to close the nasopharynx

Question 6

What are the tonsils?

What do they form?

Answer 6

The tonsils are collections of lymphatic tissue located within the pharynx. They collectively form a ringed arrangement, known as Waldeyer’s ring:
•	Pharyngeal tonsil
•	Tubal tonsils (x2)
•	Palatine tonsils (x2)
•	Lingual tonsil

Question 7

What is the function of the tonsils?

Answer 7

The tonsils are classified as mucosa-associated lymphoid tissue (MALT), and therefore contain T cells, B cells and macrophages. They have an important role in fighting infection – the first line of defence against pathogens entering through the nasopharynx or oropharynx.

Question 8

Label the oral cavity

Answer 8

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Question 9

What is the frenulum and linguinal frenulum?

Answer 9

Frenulum of lips (thin line between the lips and gums) and frenulum of tongue (underneath the tongue and is a thin line of tissue between the inferior portion of the tongue and the mucosa of the floor of the mouth). The lingual frenulum helps to anchor the tongue in your mouth and stabilise the movements of the tongue

Question 10

What is the function of the salivary glands?

What are they stimulated and innervated by?

Answer 10

They are involved in lubrication and protection from pathogens and digestions. Saliva contains amylase and lipase that breakdown carbs and fats. They are stimulated by thoughts, smells, visions and taste. The nerve path for the salivary glands is from the brain stem through the parasympathetic nervous system via the glossopharyngeal and facial nerves.

Question 11

What can removal of the salivary glands cause?

Answer 11

Removal of salivary glands can cause damage to the facial nerve passage through it such as the parotid glands causing bells pawsy – temporary weakness or paralysis of the muscles of the side of the face affected by injury.

Question 12

What are the 3 salivary glands and where are they located?

Answer 12

• Parotids: located on top of the mandibular ramus, they drain into the oral cavity via the parotid duct (20% of total saliva)
• Submandibular: located below the mandibular body, they drain into oral cavity via the submandibular (Wharton) duct (75% total saliva).
• Sublingual: located below the tongue, they drain into oral cavity via 8-20 small ducts (Rivinus ducts). It contributes to 5% of total saliva.

Question 13

Label the salivary glands

Answer 13

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Question 14

Where are the tonsils located?

Answer 14

The tonsils are a set of lymphoid organs with an immune function. Together they form the Waldeyer’s tonsillar ring. The palatine and sublingual tonsils are located at the back of the oral cavity proper/beginning of oropharynx. The tubal and pharyngeal tonsils are located in the nasopharynx, where the nose blends into the throat. Tubal tonsils surround the eustachian tube in the lateral wall of the nasopharynx.

Question 15

What is acute tonsillitis?

Answer 15

Acute tonsillitis: the patient complains of a persistent pain in the throat and ear on swallowing (possibly with fever). Opening the mouth is often difficult and painful, the tongue is coated, there is a mouth odour, the tonsils and uvula are red and swollen with white spots caused by infection.
The patient may also complain of headache, thick speech, as well as swelling and tenderness of the neck glands (lymph nodes).

Question 16

Label the tongue

Answer 16

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Question 17

What is the function of the muscles of the tongue?

Answer 17

They constitute the tongue proper and are responsible for changing the tongue’s shape during deglutition and phonation. These muscles affect the shape and size of the tongue – for example, in tongue rolling – and have a role in facilitating speech, eating and swallowing.

Question 18

Label and name the intrinsic tongue muscles

Answer 18

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Question 19

The extrinsic muscles are as follows:

Answer 19

Genioglossus
• Attachments: Arises from the mandibular symphsis. Inserts into the body of the hyoid bone and the entire length of the tongue.
• Function: Inferior fibres protrude the tongue, middle fibres depress the tongue, and superior fibres draw the tip back and down
• Innervation: Motor innervation via the hypoglossal nerve (CNXII).
Hyoglossus
• Attachments: Arises from the hyoid bone and inserts into the side of the tongue
• Function: Depresses and retracts the tongue
• Innervation: Motor innervation via the hypoglossal nerve (CNXII).
Styloglossus
• Attachments: Originates at the styloid process of the temporal bone and inserts into the side of the tongue
• Function: Retracts and elevates the tongue
• Innervation: Motor innervation via the hypoglossal nerve (CNXII).
Palatoglossus
• Attachments: Arises from the palatine aponeurosis and inserts broadly across the tongue
• Function: Elevates the posterior aspect of the tongue
• Innervation: Motor innervation via the vagus nerve (CNX).

Question 20

Label the extrinsic tongue muscles

Answer 20

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Question 21

What are the extrinsic tongue muscles innervated by?

Answer 21

All of the intrinsic and extrinsic muscles are innervated by the hypoglossal nerve (CN XII), except palatoglossus, which has vagal innervation (CN X).

Question 22

Describe the vasculature and innervation of the tonguez

Answer 22

• Motor innervation: hypoglossal nerve (CN XII)
• except palatoglossus muscle -> vagus nerve (CN X)
• Anterior 2/3 sensation: lingual nerve (branch of mandibular nerve V3)
• Anterior 2/3 taste: chorda tympany (branch of facial nerve)
• Posterior 1/3 sensation and taste: glossopharyngeal nerve (CN IX).
• The lingual artery supplies most of the muscles of the tongue

Question 23

Label the Mandible bone and inferior alveolar branch

Answer 23

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Question 24

Label the interior surface of the mandible

Answer 24

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Question 25

What is the TMJ joint?

What are the 3 articulations of the TMJ joint?

Answer 25

The temporomandibular joint (TMJ) is formed by the articulation of the mandible and the temporal bone of the cranium. It is located anteriorly to the tragus of the ear, on the lateral aspect of the face.

The temporomandibular joint consists of articulations between three surfaces; the mandibular fossa and articular tubercle (from the squamous part of the temporal bone), and the head of mandible.

This joint has a unique mechanism; the articular surfaces of the bones never come into contact with each other – they are separated by an articular disk. The presence of such a disk splits the joint into two synovial joint cavities, each lined by a synovial membrane. The articular surface of the bones are covered by fibrocartilage, not hyaline cartilage.

Question 26

What are the 4 muscles of mastication?

Answer 26

• Masseter
• Temporalis
• Medial pterygoid
• Lateral pterygoid

Question 27

What are the attachments and action of the temporalis?

Answer 27

Attachments: Originates from the temporal fossa. It condenses into a tendon, which inserts onto the coronoid process of the mandible.

Actions: retraction and elevation of the mandible.

Question 28

What are the attachments and action of the Masseter?

Answer 28

Attachments: The superficial part originates from maxillary process of the zygomatic bone. The deep part originates from the zygomatic arch of the temporal bone. Both parts attach to the ramus of the mandible.

Actions: elevation of the mandible

Question 29

What are the attachments and action of the Lateral Pterygoid?

Answer 29

Lateral pterygoid origin: crest of greater wing and lateral surface of lateral pterygoid plate of sphenoid bone

Lateral pterygoid insertion: neck of mandibular condyle

Lateral pterygoid muscle:
Mandible protraction and side-to-side movements

Question 30

What are the attachments and action of the Medial pterygoid?

Answer 30

Medial pterygoid origin: posterior maxilla and medial surface of lateral pterygoid plate of sphenoid bone

Medial pterygoid insertion: neck of mandibular condyle

Medial pterygoid muscle:
Mandible elevation, (protraction in minor part) and lateral (side to side) motion

Question 31

What is the arterial supply and nerve supply to the muscles of mastication?

Answer 31

Arterial supply:
Maxillary artery and its branches:
•	Pterygoid, deep anterior and posterior temporal and masseteric arteries supply muscles of mastication
Nerve supply:
Mandibular nerve and its branches:
•	Deep anterior and posterior temporal nerves 
•	Masseteric nerve
•	Nerve to medial pterygoid 
•	Nerve to lateral pterygoid