Chapter 88 - Salivary Glands

Question 1

What are the 4 main salivary glands in the dog and cat?

Answer 1

Parotid, mandibular, sublingual, zygomatic

Question 2

Describe the location and borders of the parotid salivary gland

Answer 2

Superficial to the vertical ear canal
Rostral - Masseter and TMJ
Caudal - sternomastoideus and cleidocervicalis
Ventral - mandibular salivary gland
Superficial - parotidoauricularis and platysma mm

Question 3

Describe the important structures intimately associated with the parotid gland

Answer 3

Facial n, maxillary a, temporal a, internal maxillary v, external acoustic meatus, stylomastoid foramen

Question 4

Where does the duct of the parotid gland travel?

Answer 4

From the ventrorostral border of the gland, over the ventral aspect of the masseter m and into the oral cavity at the upper fourth premolar

Question 5

What is the main blood supply to the parotid gland?

Answer 5

Parotid a

Question 6

Where is the zygomatic gland located?

Answer 6

Ventral and rostrolateral to the globe, within the orbit, medial to the zygomatic arch

Question 7

Where does the zygomatic duct enter the oral cavity?

Answer 7

Caudolateral to the last upper molar, 1cm caudal to the parotid papilla

Question 8

What is the main blood supply to the zygomatic gland?

Answer 8

Infraorbital a

Question 9

Describe the location of the mandibular/monostomatic sublingual gland?

Answer 9

Just caudal to the angle of the mandible, rostromedial to the bifurcation of the jugular vain into the linguofacial and maxillary v

Question 10

Where does the mandibular duct travel

Answer 10

From the gland, medial to the sublingual and ramus of the mandible, between the styloglossus and mylohyoideus mm, into the sublingual caruncle

Question 11

What is the main blood supply to the mandibular and sublingual gland?

Answer 11

glandular branch of the facial a

Question 12

Describe the anatomy of the sublingual gland

Answer 12

Monostomatic portion caudally within the capsule of the mandibular gland, polystomatic portion more rostrally as loose clusters beneath the digastricus and mylohyoideus, they empty into the sublingual caruncle

Question 13

What are the minor salivary glands?

Answer 13

Buccal, labial, lingual, tonsillar, palatine, molar

Question 14

What are the functions of saliva?

Answer 14

Lubricating food boluses, heat evaporation, reducing bacterial growth, buffering of weak acids, protection of the mucosal epithelium

Very little digestion occurs in dog and cat saliva

Question 15

Describe the character of saliva from each gland

Answer 15

Parotid and mandibular - more serous
Sublingual and zygomatic - more mucoid

Question 16

Describe the 2 phases of saliva production prior to excretion

Answer 16

1. Acinar cells absorb Na and saliva becomes Na rich
2. Columnar epithelial cells in the intralobular ducts reabsorb Na and excrete HCO3 and K

Question 17

Describe the features, diagnostics and treatment of sialodenosis

Answer 17

Non-inflammatory, non-neoplastic bilateral painless swelling of the salivary glands, usually mandibular
may be a form of limbic epilepsy
Usually causes dysphagia and gagging/lip-licking signs
Treatment with phenobarbital

Question 18

Describe sialadenitis and necrotizing sialometaplasia

Answer 18

Enlarged, painful salivary glands with systemic illness
Treatment with surgery is not reliable
Treat with phenobarb
Assess for oesophageal disease

Question 19

Describe a sialocele

Answer 19

Collection of saliva within subcut tissues, produces a cavity lined by inflammatory connective tissue (not a true epithelial lined cyst). Caused by leakage of fluid from a duct or gland, usually sublingual

Question 20

What are the four main presentations of sialocele and their causative gland

Answer 20

Exophthalmus - zygomatic
Laboured breathing - pharyngeal sialocele, usually the mandibular or sublingual gland
Dysphagia - sublingual
Intermandibular or ventral cervical swelling - mandibular or sublingual

Question 21

Describe sialoliths in dogs and cats

Answer 21

Obstruction of the salivary gland caused by a stone, usually the parotid gland, swelling that may come and go on the lateral face, diagnosed on CT, treatment can be excision of the gland, excision of the stone, R&A, ligation of the duct

Question 22

What is the most common neoplasia of the salivary glands

Answer 22

Adenocarcinoma or acinic carcinoma

Question 23

What glands are most affected by neoplasia

Answer 23

Mandibular and parotid

Question 24

What is the met rate of salivary gland neoplasia?

Answer 24

Dog - LN 17%, distant 8%
Cat - LN 39%, distant 16%

Question 25

MST for salivary gland neoplasia?

Answer 25

Largely unknown, 74-550d

Question 26

Describe the ventral approach to the mandibular salivary gland

Answer 26

Dorsal recumbency, incision along the ventromedial border of the mandibular ramus to 5cm caudal to the angle, incise through platysma over the gland, identify the maxillary and linguofacial vein to find the gland, incise the capsule, remove the glands and ligate the vessel medially, disect out the duct rostrally to the level of the lingual nerve, remove glands and continue rostrally if necessary, transect the mylohyoideus and tunnel under the digastricus to remove all polystomatic portion, drain any saliva pockets

Question 27

Describe approach to the zygomatic gland

Answer 27

Incise horizontally over the zygomatic arch, incise the insertion of the masseter on the ventral aspect, ostectomy of the zygomatic arch, retraction of the ortibal fat

Question 28

Describe parotid sialadenectomy

Answer 28

Facial n injury is likely
Incise over the vertical ear canal to the angle of the mandible, incise platysma and parotidoauricularis mm, ligate and divide the caudal auricular v, dissect cautiously in the medial aspect, ligate and divide the duct