Facial nerve

Question 1

Facial nerve emerges from which foramen?

Answer 1

Stylomastoid foramen

Question 2

Course of frontal branch of facial nerve

Answer 2

Follows a path from 0.5 cm below the tragus to a point 1.5 cm above the lateral brow - known as Pitanguy line

Question 3

Levels where frontal branch of facial nerve is deep and superficial

Answer 3

Frontal branch of facial nerve is deep to SMAS at least until the level of zygomatic arch. Once it crosses the zygomatic arch, it steadily becomes more superficial to lie within or just deep to the SMAS.

Question 4

Course of zygomatic and buccal branches of facial nerve

Answer 4

Zygomatic and buccal branches of facial nerve lies deep to the parotidomasseteric fascia, but upon exiting the parotid gland, it lies over the masseter.

Question 5

Injury of frontal branch of facial nerve usually occurs at which level?

Answer 5

When the frontal branch crosses the zygomatic arch, where it becomes superficial or lies within the SMAS. In this situation, during facelift, it is most susceptible to injury.

Question 6

Injury to zygomatic branch of facial nerve occurs at which level?

Answer 6

After the zygomatic branch crosses the parotid gland, it overlies the masseter muscle. The zygomatic branch is vulnerable during release of zygomatic retaining ligaments.

Question 7

Injury to buccal branch of facial nerve can occur during?

Answer 7

During dissection of buccal fat pad

Question 8

Course of marginal mandibular branch of facial nerve

Answer 8

• Exits the parotid gland 4 cm below the base of earlobe, just anterior to angle of mandible.
  81% of cases, the nerve courses above the mandibular border.
• It runs superficial to facial artery and vein, can be identified where the facial vessels cross the mandibular border, just anterior to insertion of masseter.
• Remains deep to deep fascia along most of its course, thus injury is quite rare.

Question 9

Course of cervical branch of facial nerve

Answer 9

Exits the parotid gland just anterior to angle of mandible and penetrates the deep fascia to travel in the subplatysmal plane.

Cervical branch is more superficial hence it is more commonly injured. Injury of cervical branch causes weakness of lip depression, preservation of ability to evert and purse the lips.