The Mandible and Maxilla Flashcards
Cat vs dog - who tolerates mandibulectomy/maxillectomy more?
Dog
What are the 4 components of the mandible?
Right and left half – hemi-mandible
Horizontal component – body
Vertical component – ramus.
What joins the two halves of the madible at the rostral aspect?
Fibrous symphysis
The vascular supply to the mandible comes from? A branch of what?
inferior alveolar artery, a branch of maxillary artery.
Where dos the inferior alveolar a. enter the mandible? Travel and exit?
This enters through the mandibular foramen on the medial aspect of angle of the mandible, travels rostrally within the marrow cavity of the mandible and exits laterally through the mental foramen just caudal to the canine tooth
Which artery must be cauterised or ligated and transected during mandibulectomy?
mandibular artery
What provides sensory innervation to the mandible and lower teeth?
mandibular nerve (a branch of trigeminal)
How does the mandibular nerve (a branch of trigeminal) course? and change?
entering at the mandibular foramen, coursing rostrally as the inferior alveolar nerve through the marrow cavity and exiting at the mental foramen as the mental nerve.
The ducts of the mandibular and sublingual salivary glands run where in relation to the body of the mandible
medial
The ducts of the mandibular and sublingual salivary glands open where?
Sublingual papilla
What happens if you transect The ducts of the mandibular and sublingual salivary glands during mandibulectomy?
Not a concern
3 bones of the maxilla?
Maxillary
Incisive (premaxilla)
Nasal
What teeth are containe in the:
A) Maxillary bone?
B) Incisive bone?
A) Canines, premolars, molars
B) Incisors
The vascular supply of the maxilla comes from branches of?
Maxilary artery
Where does the major palatine a. run ?
Through the caudal nasal cavity and caudal portion of the hard palate before running rostrally, ventral to hard palate, midway between the midline and the maxillary teeth.
Where does the infraorbital a. run, pass and exit?
Runs through the caudal nasal cavity dorsal to the major palatine artery, passing through the maxillary foramen and infraorbital canal of the maxilla, exiting at the infraorbital foramen just rostral to the carnassial tooth.
Which vessels may be ligated/transected in a maxxilectomy?
Both the major palatine artery and the infraorbital artery
The nerve supply to the maxilla is from the ? that supplies the teeth?
infraorbital nerve (a branch of the maxillary nerve)
Where will the infraorbital a. be transected in a maxillectomy?
within the infraorbital foramen
The parotid salivary gland duct terminates where?
At a papilla just lateral to the fourth upper pre-molar tooth and the zygomatic salivary ducts terminate just caudal to this
T or F
These ducts can be transected without concern during maxillectomy.
true
Where does Digastricus run from and to?
Runs from the occipital region of skull to the ventral border of the body of the mandible
Where does the Masseter run from and to?
Runs from the zygomatic arch to the lateral surface of the caudal body and ramus of the mandible
Where does the Pterygoideus (A lateral and medial muscle ) run from and to?
run from the pterygoid, sphenoid and palatine bones to the angular process of the ramus
Where does the Temporalis run from and to?
Extends from the temporal region to the dorsal ramus
What is the function of the digastricus?
Open the jaw
What is the function of the Masseter and Temporalis?
Close the jaw
What is the function of the Pterygoideus?
Close the jaw and pull to the side for chewing
he most frequently occurring oral tumours in dogs are? (6 in order)..
- malignant melanomas,
- non-tonsillar squamous cell carcinomas,
- fibrosarcomas,
- osteosarcomas,
- canine acanthomatous ameloblastomas
- fibrous/ossifying epulides
Malignant melanoma:
A) Age?
B) Breed size?
C) Colour of growth?
D) Met rate?
E) Met location?
A) Older
B) Small breed
C) Often dark, 33% amelanotic
D) 80%
E) LN; not just ipsilateral side!
Squamous cell carcinoma (non-tonsillar):
A) Age?
B) Breed size?
C) Appearance?
D) Met rate?
E) Met location?
A) Older
B) Large
C) Flat, ulcerated, minimally external
D) 20%
E) Local
Fibrosarcoma:
A) Age?
B) Breed size?
C) Breed? (2)
D) Arise from?
E) Met rate?
F) Met location?
G) What anatomy is commonly involved?
A) Middle age- Older
B) Large
C) Labrador + golden retriever
D) Gingiva near maxillary carnassial
E) 35%
F) Local
G) Hard palate
Osteosarcoma:
A) Breed size?
B) (Origin? (2)
C) Met location?
A) Medium + Large
B) Maxillary and mandibular
C) Lung
Do axial osteosarcomas vs appendicular osteosarcoma have a better prognosis post-operatively?
axial osteosarcomas
Canine acanthomatous ameloblastoma (CAA):
A) Breed size?
B) Arise from what epithelium?
C) Met?
D) Invade?
E) Oten arise from the rostral mandible or maxilla, what happens 2ry to this?
F) Tx of choice?
A) Medium - large
B) Odontogenic
C) No!
D) Locally
E) Displace incisors
F) mandibulectomy/maxillectomy.
Fibromatous epulides arise from?
Peridontal ligament
Epulis arise from?
Gingiva
Fibrous/ossifying epulides are often located where?
Pre-maxillary
Fibrous/ossifying epulides; Local excision without bone removal often provides excellent local control but likelihood of cure is improved if?
if the tooth and a small margin of the alveolar bone is removed with an air drill.
Which of these are more commonly seen in older, small-breed dogs?
Osteosarcoma
Fibrosarcoma
Malignant melanoma
Malignant melanoma
What is involved in pre op staging of oral tumours?
Thorax image - radiograph vs cT
Pre op biopsy (deep into lesion)
LN asessment; ideally mandibular, parotid, retropharyngeal nodes bilaterally
What is the issue of using x rays to visualise oral tumours?
Often under-estimate the degree of bony involvement due to the delay in lysis appearing radiographically
T or F
Pre-operative biopsy is useful to determine the degree of resection required.
True
T or F
Compared to MRI, CT is superior to assess tumour bone margins.
True
T or F
Optimal staging of oral tumour would include removal of mandibular and parotid nodes unilaterally.
Optimal staging would include removal of all three nodes (mandibular, parotid, and retropharyngeal) bilaterally.
Follow-up intra-oral examinations should be performed every ? following surgery
3-4 months
One year survival rates of 70-90% have been reported following aggressive surgical management of oral tumours, with reported recurrence rates ?
50%
Do you know why caudally based tumours have a poorer prognosis in general? (2)
longer to notice them,
more advanced at presentation
Which tumours generally have the highest survival rates following surgical excision? (2)
Oral (non-tonsillar) SCC and acanthomatous ameloblastoma
Why do fibrosarcoms have a higher recurrence rate? (2)
invasive
Often located in the central or caudal maxilla
Mean survival times for malignant melanoma?
1 year
When is Radiation therapy (RT) is indicated indicated? (3)
high potential for local recurrence,
- incomplete histologic margins,
- large tumours
- tumours located in the caudal oral cavity.
How to access the nasopharynx and achieve biopsy samples or remove benign tumours?
How to reduce risk of dehiscence and aid reconstruction?
Soft palate split through midline
Leave distal aspect in tact
Radiation therapy works better against microscopic disease so should be used pre or post op?
Post op
Platinum-based chemotherapy (e.g., carboplatin) has been used to treat ? with a significant reduction in tumour volume reported.
malignant melanoma
Most common feline oral tumour?
SCC
SCC in cats usually arise from what mucosa? (2)
Gingiva
Sublingual
SCC in cats:
A) How invasive?
B) 20% met to?
C) How common is distant met?
A) Highly
B) LN
C) Rare
Most SCC in cats occur where?
Caudal to canines
Maxillary SCC masses in cats invade where?
Periocular
Tongue SCC masses in cats invade where?
Sublingually
Advanced imaging is particularly recommended in cats SCC. Why?
Highly invasive; often extend within the medulla of the mandibular bone far beyond their gross limits
After what % of mandible is excised, long-term inappetence is a concern in cats?
50%
Feeding tubes should be placed following mandibulectomy in cats; why?
Often do now eat!
