Parotid Region and Facial Nerve

Question 1

Where is the parotid region?

Answer 1

Anterior to ear and inferior to zygomatic arch

Question 2

Where is the parotid gland?

Answer 2

Enclosed in the parotid sheath
Extends between zygomatic arch and lower border or between the SCM, external acoustic meatus and masseter

Question 3

Where does the parotid duct run?

Answer 3

Passes anteriorly and horizontally before piercing the buccinator to enter the oral cavity near the upper 2nd molar

Question 4

What structures are found embedded in the parotid gland?

Answer 4

Retromandibular vein
External carotid artery (posterior auricular, maxillary and superficial temporal)
Parotid lymph nodes
CNVII - but doesn’t innervate the parotid

Question 5

Describe arterial supply of the parotid gland

Answer 5

ECA passes deep or enters the parotid giving off the posterior auricular artery then splits to give rise to its terminal branches - superficial temporal and maxillary

Question 6

Describe venous drainage of the parotid gland

Answer 6

Maxillary and superficial temporal veins
These veins join to give the retromandibular vein

Question 7

Describe parasympathetic innervation of the parotid gland

Answer 7

Secretomotor innervation to produce saliva
Preganglionic fibres from CNIX to otic ganglion in the tympanic and lesser petrosal nerve
Postganglionic fibres from otic ganglion to parotid gland through the auriculotemporal nerve (CV3)

Question 8

Describe sympathetic innervation of the parotid gland

Answer 8

From the superior cervical ganglion and the nerve plexus on the external carotid artery
This results in vasoconstriction and some reduction in the volume of saliva that leads to dry mouth

Question 9

What is the intratemporal portion of the facial nerve?

Answer 9

The first part of the nerve from where it exits the pons to where it exits the skull

Question 10

Describe the path of the intratemporal portion of the facial nerve

Answer 10

Exits the pons as 2 roots - motor root and S and PS root
These roots enter the internal acoustic meatus and then the facial canal
The roots fuse here and enlarge, forming the geniculate ganglion
The greater petrosal nerve branches here and supplies PS innervation to the nasal and lacrimal glands
Then runs downwards and gives off 2 branches - nerve to stapedius and chorda tympani
Facial nerve exits the skull through the stylomastoid foramen

Question 11

What does the nerve to stapedius supply?

Answer 11

Motor to stapedius muscle of the middle ear

Question 12

What does the chorda tympani supply?

Answer 12

Hitchhikes with the lingual nerve to supply taste and sensation to anterior 2/3 of tongue

Question 13

What is the extratemporal portion of the facial nerve?

Answer 13

The second part of the nerve from where it exits the skull at the stylomastoid foramen

Question 14

Describe the path of the extratemporal portion of the facial nerve

Answer 14

2 branches are given off - posterior auricular and digastric branches
Main nerve then enters the parotid gland

Question 15

Describe the course of the facial nerve in the parotid gland

Answer 15

In the parotid, the facial nerve divides into temporofacial and cervical facial branches which then form the carotid plexus - this goes on to give 5 branches:
Temporal , zygomatic, buccal, marginal mandibular, cervical

Question 16

What does the temporal branch supply?

Answer 16

Muscles of the temple, forehead and supraorbital area

Question 17

What does the zygomatic branch supply?

Answer 17

Muscles of infraorbital area, the lateral nasal area and the upper lip

Question 18

What do the buccal branches innervate?

Answer 18

Muscles of the cheek, the upper lip and the corner of the mouth

Question 19

What does the marginal mandibular branch supply?

Answer 19

Muscles of the lower lip and chin

Question 20

What does the cervical branch innervate?

Answer 20

Platysma

Question 21

What is static reconstruction?

Answer 21

Facial reconstruction after 2 years of paralysis with no improvement
Involves the creation of a sling that is attached at the mouth and the side of the face to create facial symmetry at rest

Question 22

What can be used for static construction?

Answer 22

Various techniques
Can use the tensor fasciae latae from the lateral leg
Can use a small gold weight within the upper eyelid to assist closure of the eye

Question 23

How can tumours of the parotid gland affect the facial nerve?

Answer 23

Most often benign however they can increase in size and disrupt surrounding tissues
A total or partial parotidectomy to remove the tumour is recommended
Facial nerve injury or bruising is a common risk of this procedure

Question 24

Describe a great auricular nerve graft

Answer 24

It can be used as a graft for the facial nerve if it is known that damage to this nerve will occur during a procedure
Due to close relation of this nerve to surgical site during parotidectomy, nerve graft can be performed at the same time

Question 25

What is mumps?

Answer 25

A viral infection that was commonly seen in children
Symptoms are general and include fever, headache and joint pain
Most common and recognisable symptom is swelling of the parotid gland