Lecture 7: Face and Parotid

Question 1

What are the layers of the scalp?

Answer 1

Skin

Connective tissue (dense) - contains neurovascular structures

Aponeurosis

Loose connective tissue - Facilitates movement of the scalp over the calvaria (infection tends to be in this layer)

Pericranium

Question 2

Innervation? Blood supply/drainage?

Answer 2

Innervation is by two main sources:

1. Cranial nerve V
2. Cervical nerves -posterior rami (C2 and C3 - inc greater auricular as well as leasser, great and third occipital nerve)

Blood supply is mostly by branches of the external crotid artery (post auricular and superficial temporal) but also from the opthalmic artery (+supraorbital and supratrochlear), a branch of the internal carotid

Question 3

Muscles of facial expression?

Answer 3

1. Platysma
2. Occipitofrontalis (anterior/frontalis and posterior/occipitalis belly)
3. Auricularis muscles (superior, anterior and posterior)
4. Obicularis occuli
5. nasalis muscles
6. upper and lower lip muscles
7. buccinator (cheeks)

• all innervated by the facial - CN VII

Question 4

Sensory innervation of the face?

Answer 4

They are from the trigeminal nerve

1. opthalmic
2. maxillary (infraorbital, zygomaticofacial and zygomaticotemporal)*
3. mandibular (Buccal, mental nerve, auriculotemporal)*

(remember the transverse cervical does the ant neck)

Question 5

Facial nerve pathway from exiting the skull?

Answer 5

The facial nerve leave via the stylomastoid foramen and immediately gives off the posterior auricular nerve (that passes back up to supply occipitalis belly of occipitofrontalis)

The next branch supplies the posterior belly of digastric and the stylohyoid muscle.

The facial nerve then enters the parotid gland and splits into the upper temporozygomatic and lower cervicofacial branch.

Upon leaving the ant boarder of the parotid ther is the temporal*, sygomatic, buccal, marginal mandibular* and cervical branch

* very superficial and commonly damaged.

Question 6

Where does the parotid gland sit? Innervation?

Answer 6

The superficial part sits on the ramus below the sygomatic arch and may go below the angle of the mandible. The deep part wraps around the ramus and sits deep to it

• Sensory inervation by V3 (gland) and C2 (parotid fascia)
• Secretorymotor Parasympathetic fibres are mainly IX and V3
• Sympathetic fibres are the sup. cervical ganglion via ECA

Question 7

The Parotid duct? surface anatomy and opening? Relations?

Answer 7

The middle third of the line connecting the lower boarder of the tragus and the cheilion 1.5cm above and below this. The line between the canthu of the eye and angle of the mandible always crosses the posterior part of the duct just after it emerges from the gland.

The facial nerve runs though the parotid gland superficial to the retromandibular vein and external carotid artery.

• Exits gland to run along the masseter muscle
• dives into the buccinator at the anterior edge of masseter
• opens next to second molar

Question 8

Damage to the marginal mandibular, temporal or facial nerve?

Answer 8

Marginal mandibular - results in lip drooping with compensation overtime from the upper lip muscles = resting snarling face

Temporal nerve - causes ptosis of the brow

Bell’s palsy - droopiness, may effect taste and tear and salivary production