Parotid gland

Question 1

Parotid region border

Answer 1

Superiorly by zygomatic arch
Inferiorly by angle and inferior border of mandible
Anteriorly by masseter (ant border)
Posteriorly by SCM & external ear
Medially by ramus of mandible

Question 2

Parotid regions contents

Answer 2

Parotid gland and duct
Terminal branch of facial N.
Retromandibular vein
External carotid A.
Masseter

Question 3

Structures present inside the gland

Answer 3

Facial N.
External carotid A.
Retromandibular V.

Question 4

Where does the Stensen’s duct open

Answer 4

Opens into vestibule of the mouth opposite to crown of upper 2nd molar tooth.

Question 5

Blood supply, venous drainage and lymphatics of the parotid gland

Answer 5

Branches of the external carotid A.
External jugular V.
Parotid lymph nodes.

Question 6

Nerve supply of the parotid gland

Answer 6

Parasympathetic (secretomotor)
nerve cell bodies in inferior Salivatory nucleus
Preganglionic fibers carried by glossopharyngeal N and then after passing jugular foramen, by the tympanic N (branch of CN XII) up until tympanic plexus & then lesser petrosal N up until Otic Ganglion. Then postganglionic nerve fibers by auriculotemporal N (CN V3) - parotid branch.

Sympathetic (Vasomotor)
Superior cervical ganglia (nerve cell bodies)
and then preganglionic fibers carried by external carotid N plexus on the external carotid A.
Post ganglionic by lesser petrosal N before otic ganglion & auriculotemporal N after otic ganglion. (The lesser petrosal nerve does not synapse at the Otic ganglion).

Sensory innervation of the parotid gland :auriculotemporal N.
Cutaneous innervation over parotid region : Greater Auricular N.

Question 7

What is particular about the auriculotemporal N.

Answer 7

The auriculotemporal nerve is a tributary of the mandibular division of CN V, the trigeminal nerve. It carries sensory (cutaneous) , sympathetic fibers (vasomotor), and parasympathetic fibers (secreteomotor) as well as sympathetic fibers of sweat glands.

Question 8

What is Frey Syndrome

Answer 8

Rewireing of Auriculotemporal N after parotidectomy. During regeneration, secretomotor fibers of the Auriculotemporal N get mixed up with sympthetic fibers which innervate the sweat glands instead of producing saliva. Area becomes flushed, hot & painful.

Question 9

What are the 5 branches of the facial N. in the parotid gland?
‘‘The Zebra Bit My Cervix’’

Answer 9

Temporal
Zygomatic
Buccal
Marginal mandibular
Cervical

Question 10

Where does the Wharton’s duct open ?

Answer 10

Floor of mouth, on summit of sublingual papilla, at side of frenulum of tongue.

Question 11

Blood supply, venous drainage & lymphatics of submandibular gland

Answer 11

Facial Artery
Common facial vein or lingual vein.
Submandibular lymph nodes.

Question 12

Nerve supply of submandibular and sublingual glands

Answer 12

Parasympathetic (Secretomotor)
Nerve cell bodies in superior salivatory nucleus
Preganglionic carried by : corde tympani (branch of facial N) + lingual N (from trigeminal) prior to synapsing on the submandibular ganglion.
Postganglionic : unknown

Sympathetic
Nerve cell bodies in T1 spinal segment & preganglionic to superior cervical ganglion, where post-synaptic vasoconstrictive fibres travel as a plexus on the internal and external carotid arteries, facial artery and finally the submental arteries to enter each gland. Increased sympathetic drive reduces glandular bloodflow through vasoconstriction and decreases the volume of salivary secretions, resulting in a more mucus and enzyme-rich saliva.

Question 13

Corde Tympani functions:

Answer 13

Carries parasympathetic fibers
Taste fibers

Question 14

Lingual N functions:

Answer 14

Carries parasympathetic fibers
General sensation of the anterior portion of the tongue