Oral surgery

Question 1

What does the hypoglossus do?

Answer 1

Retract the tongue

Question 2

What does the genioglossus do?

Answer 2

Protrude the gongue

Question 3

What does the mylohyoid do?

Answer 3

Raises floor of the mouth

Question 4

Where does the geniohyoid connect?

Answer 4

Genial tubercles to hyoid

Question 5

What does the digastric do? connect to? innervated by?

Answer 5

Opens jaw
Digastric fossa to hyoid bone
Innervated by:
V - anterior belly
VII - posterior belly

Question 6

Name the 4 extrinsic muscles of the tongue?

Answer 6

• Styloglossus (XII) - styloid to tongue. Retracts + elevates the tongue.
• Genioglossus (XII) - genial tubercles to tongue. Protrudes + depresses the tongue
• Hypoglossus (XII) - Hyoid to tongue. Retracts + depresses the tongue.
• Palatoglossus (X) - palate to tongue. Elevation of posterior tongue.

Question 7

What are the intrinsic muscles of the tongue?
Names (4)
Function?
Innervation?

Answer 7

The intrinsic muscles originate and attach to other structures within the tongue.

There are four paired intrinsic muscles of the tongue and they are named by the direction in which they travel –
> superior longitudinal,
> inferior longitudinal,
> transverse
> vertical muscles of the tongue.

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.

The motor innervation to the intrinsic muscles of the tongue is via the hypoglossal nerve (CN XII).

Question 8

What are the extrinsic muscles of the tongue and what are they innervated by?

Answer 8

The extrinsic muscles of the tongue originate from structures outside the tongue and insert onto it.

Genioglossus, Hyoglossus and Styloglossus are innervated by the hypoglossal nerve – with the exception of the Palatoglossus, which is innervated by the vagus nerve.

Question 9

Genioglossus: attachments? function? innervation?

Answer 9

The genioglossus muscle is a large, thick muscle, which contributes significantly to the shape of the tongue.

Attachments: Arises from the mandibular symphysis. It inserts onto the body of the hyoid bone and the entire length of the tongue.

Function: Protrusion (‘sticking the tongue out’) and depression of the tongue.

Innervation: Hypoglossal nerve.

Question 10

Hyoglossus: attachments? function? innervation?

Answer 10

The hyoglossus muscle is located in the floor of the oral cavity, immediately lateral to the geniohyoid.

Attachments: Arises from the hyoid bone and inserts onto the lateral aspect of the tongue.

Function: Depression and retraction of the tongue.

Innervation: Hypoglossal nerve.

Question 11

Styloglossus: Attachments? Function? Innervation?

Answer 11

The styloglossus is a thin, paired muscle, located on either side of the oropharynx.

Attachments: Originates from the styloid process of the temporal bone and inserts onto the lateral aspect of the tongue.

Function: Retraction and elevation of the tongue.

Innervation: Hypoglossal nerve.

Question 12

Palatoglossus: attachments? Function? Innervation?

Answer 12

The palatoglossus muscle is also associated with the soft palate – and is therefore innervated by the vagus nerve.

Attachments: Arises from the palatine aponeurosis and inserts broadly along the tongue.

Function: Elevation of the posterior tongue

Innervation: Vagus nerve.

Question 13

Which nerves supply the 1) sensation and 2) taste the the anterior 2/3rd of the tongue?

Answer 13

1) In the anterior 2/3, general sensation is supplied by the trigeminal nerve (CNV). Specifically the lingual nerve, a branch of the mandibular nerve (CN V3).
* Lingual nerve (V3)

2) Taste in the anterior 2/3 is supplied from the facial nerve (CNVII). In the petrous part of the temporal bone, the facial nerve gives off three branches, one of which is chorda tympani. This travels through the middle ear, and continues on to the tongue.
* Chorda tympani (VII)

Question 14

What nerve supplies sensation and taste the the posterior 1/3 or the tongue?

Answer 14

Both touch and taste are supplied by the glossopharyngeal nerve (CNIX).
* Glossopharyngeal nerve (IX)

Question 15

Name the 4 intrinsic muscles of the tongue? What are they all innervated by?

Answer 15

1. Superior longitudinal
2. Inferior longitudinal
3. Transverse
4. Vertical

–> Hypoglossal nerve (XII)

Question 16

What is the arterial and venous supply to the tongue?

Answer 16

The arterial supply to the tongue is mainly from the lingual artery (a branch of the external carotid artery). There are also contributions from the tonsillar branch of the facial artery.

Venous drainage is by the lingual vein – which empties into the internal jugular vein.

Question 17

What is the lymphatic draining of the 1) anterior and 2) posterior part of the tongue?

Answer 17

The lymphatic drainage of the tongue is as follows:

Anterior two thirds – initially into the submental and submandibular nodes, which empty into the deep cervical lymph nodes

Posterior third – directly into the deep cervical lymph nodes

Question 18

What is the foramen cecum?

Answer 18

The foramen cecum is a blind-ended pit located in the midline of the tongue at the junction of the anterior 2/3 and posterior 1/3.

Question 19

What innervates the maxillary teeth?

Answer 19

Branches of the maxillary division of trigeminal.
- Anterior superior alveolar nerve (ASAN) supplies incisors to canines.
- Middle superior alveolar nerve (MSAN) supplies premolars and MB root of 1st molar
- Posterior superior alveolar nerve (PSAN) supplies molars.

Question 20

What is the blood supply to the maxillary teeth?

Answer 20

Branches of maxillary artery:
- Anterior superior alveolar artery
- Middle superior alveolar artery
- Posterior superior alveolar artery.

Question 21

What innervates the mandibular teeth?

Answer 21

Inferior alveolar nerve which is a branch of the mandibular division of trigeminal nerve. (V3)

Question 22

What is the blood supply of the mandibular teeth?

Answer 22

Inferior alveolar artery (branch of the maxillary artery)

Question 23

What bones make up the hard palate?

Answer 23

The hard palate forms the anterior aspect of the palate.

The underlying bony structure is composed of (i) palatine processes of the maxilla; and (ii) horizontal plates of the palatine bones.

Question 24

What are the 3 foramina in the hard palate?

Answer 24

1. Incisive canal – located in the anterior midline, transmits the nasopalatine nerve and descending palatine artery.
2. Greater palatine foramen – located medial to the third molar tooth, transmits the greater palatine nerve and vessels
3. Lesser palatine foramina – located in the pyramidal process of the palatine bone, transmits the lesser palatine nerve and lesser palatine artery.

Question 25

What is the anatomy of the soft palate?

Answer 25

• The soft palate is located posteriorly. It is mobile, and comprised of muscle fibres covered by a mucous membrane.
• Anteriorly, it is continuous with the hard palate and with the palatine aponeurosis. The posterior border of the soft palate is free (i.e. not connected to any structure), and has a central process that hangs from the midline – the uvula.
• The soft palate also forms the roof of the fauces; an area connecting the oral cavity and the pharynx. Two arches bind the palate to the tongue and pharynx; the palatoglossal arches anteriorly and the palatopharyngeal arches posteriorly. Between these two arches lie the palatine tonsils, which reside in the tonsillar fossae of the oropharynx.

Question 26

What are the 5 muscles of the soft palate, their attachment, function and innervation?

Answer 26

There are five muscles which give the actions of the soft palate.

They are all innervated by the pharyngeal branch of the vagus nerve (CN X) – apart from Tensor veli palatini – which is innervated by the medial pterygoid nerve (a branch of CN V3).

1. Tensor Veli Palatini
   > Attachments: Originates from the medial pterygoid plate of the sphenoid and inserts into the palatine aponeurosis.
   Function: Tenses the soft palate.
2. Levator Veli Palatini
   > Attachments: Arises from the petrous temporal bone and the eustachian tube, before inserting into the palatine aponeurosis.
   > Function: Elevation of the soft palate.
3. Palatoglossus
   > Attachments: Originates from the palatine aponeurosis, and travels anteriorly, laterally and inferiorly to insert into the side of the tongue.
   > Function: Pulls the soft palate towards the tongue.
4. Palatopharyngeus
   Attachments: Arises from the palatine aponeurosis and the hard palate, and inserts into the upper border of the thyroid cartilage.
   > Function: Tenses soft palate and draws the pharynx anteriorly on swallowing.
5. Musculus Uvulae
   > Attachments: Arises from the posterior nasal spine and the palatine aponeurosis, and inserts into the mucous membrane of the uvula.
   > Function: Shortens the uvula.

Question 27

What is the arterial and venous supply of the palate?

Answer 27

The palate receives arterial supply primarily from the greater palatine arteries, which run anteriorly from the greater palatine foramen.

In addition, the anastomosis between the lesser palatine artery and ascending palatine artery provide collateral supply to the palate.

Venous drainage is into the pterygoid venous plexus.

Question 28

How the the palate innervated?

Answer 28

Sensory innervation of the palate is derived from the maxillary branch of the trigeminal nerve (CN V). The greater palatine nerve innervates most of the glandular structures of the hard palate.

The nasopalatine nerve innervates the mucous membrane of the anterior hard palate and the lesser palatine nerves innervate the soft palate.

Question 29

How does cleft lip occur?

Answer 29

Cleft lip – occurs when the medial nasal prominence and maxillary prominence fail to fuse.

Question 30

How does cleft palate occur?

Answer 30

Cleft palate – can occur in isolation when the palatal shelves fail to fuse in the midline, or in combination with cleft lip.

Question 31

What epithelium is attached to the superior and inferior aspect of the hard palate?

Answer 31

The hard palate is covered superiorly by respiratory mucosa (ciliated pseudostratified columnar epithelium) and inferiorly by oral mucosa (stratified squamous epithelium).

Question 32

What is hyperalgesia and allodynia?

Answer 32

Hyperalgesia – increased sensitivity to pain

Allodynia – pain from a usually non-painful stimulus

These could both be symptoms of trigeminal neuralgia.

Question 33

What is the journey of the maxillary division of trigeminal?

Answer 33

After arising from the trigeminal ganglion, the maxillary nerve passes through the lateral wall of the cavernous sinus, before leaving the skull through the foramen rotundum. It gives rise to numerous sensory branches:

Superior alveolar nerve (anterior, posterior and middle)
Middle meningeal nerve
Infraorbital nerve
Zygomatic nerve
Inferior palpebral nerve
Superior labial nerve
Pharyngeal nerve
Greater and lesser palatine nerves
Nasopalatine nerve

Question 34

What do the ASAN, MSAN and PSAN exit and what do they innervate?

Answer 34

Anterior superior alveolar nerve
> Exits via the infraorbital foramen
> Innervates anterior maxillary antrum and incisor and canine teeth

• Middle superior alveolar nerve
  > Exits via infraorbital foramen
  > Innervates medial and lateral maxillary antrum and premolars
• Posterior superior alveolar nerve
  > Exits via the pterygomaxillary fissure
  > Innervates the posterior maxillary antrum and maxillary molars

Question 35

What is the mandibular teeth supplied by? What is the journey of this nerve - what does its branches innervate?

Answer 35

Mandibular teeth are primary supplied by the inferior alveolar nerve, which is a branch of the mandibular nerve (V3). It carries both sensory and motor neurones, and exits via the foramen ovale.

• The inferior alveolar nerve carries both sensory and motor axons to and from the respective trigeminal nuclei.
• After branching from its parent nerve it gives rise to the mylohyoid nerve, a motor nerve to the mylohyoid and anterior digastric muscles.
• The remaining sensory axons enter the mandibular canal, a narrow tunnel running through the mandible. Within this canal, the nerve provides branches to the mandibular teeth.
• The nerve emerges through the mental foramen as the mental nerve. This provides sensory innervation to the lower lip and chin.

Inferior Dental Nerve (V3)
> Descends to the lateral pterygoid muscle, before
then entering the mandibular foramen
> Supplies lower molar and second premolar teeth

Mental nerve (V3)
> Exits via mental foramen
> Supplies chin, lower lip, facial gingiva and
mucosa from second premolar anteriorly

Incisive nerve (V3)
> Supplies teeth and PDL from first premolar anteriorly