Lecture 10 and (11?): Face and Parotid

Question 1

What is the Scalp?

Answer 1

The scalp is a multilayered structure extended anteriorly from the superciliary arches to the external occipital protuberance and the superior nuchal lines posteriorly.

It continues laterally down to the zygomatic arch.

It consist of 5 layers (SCALP); Skin, Connective tissue (dense), Aponeurotic layer, Loose connective tissue and Pericranium.

The first three layers are anchored tightly together.

The dense connective tissue layer contains the
neurovascular structures.

The loose connective tissue facilitates movement
of the scalp over the calvaria. Infection tends to
localise and spread through this layer because of
its consistency.

Question 2

What are the 5 layers of the Scalp?

Answer 2

It consist of 5 layers (SCALP); Skin, Connective tissue (dense), Aponeurotic layer, Loose connective tissue and Pericranium.

The first three layers are a_nchored tightly_ together.

The dense connective tissue layer contains the
neurovascular structures.

The loose connective tissue facilitates movement
of the scalp over the calvaria. Infection tends to
localise and spread through this layer because of
its consistency.

Question 3

Describe the Blood supply and the venous drainage of the Scalp

Answer 3

Blood supply:

Arteries supplying the scalp are branches of external carotid artery (and some internal) or ophthalmic artery (branch of internal carotid artery).

• Branches of o_phthalmic artery_ (supratrochlear and supra-orbital) supply anterior and superior aspects of scalp.
• Branches of external carotid artery (superficial temporal, posterior auricular, and occipital) supply lateral and posterior aspects of scalp.

Venous drainage: Similar pattern of the arteries

Question 4

Describe the Nerve supply to the scalp

Answer 4

Two major sources provide the sensory innervation of the scalp:

Trigeminal Nerve and cervical nerves (spinal cord level C2 and C3 including the great auricular nerve and the lesser, great and third occipital nerve).

Anatomists divide innervation into anterior and posterior to ears and head vertex.

Anterior to Ears and Vertex

• Branches of trigeminal nerve (V1, V3) innervate anterior region, including supratrochlear, supra-orbital, zygomaticotemporal, and auriculotemporal nerves.
• Occipitofrontalis muscle is a muscle of facial expression, so innervated by facial nerve (VII).

Posterior to Ears and Vertex

• Branches of C2 and C3 cervical nerves innervate posterior region, including great auricular, lesser/great/third occipital nerve
  
  • Great auricular and lesser occipital nerve are branch of cervical plexus, arises from anterior rami of C2/3 spinal nerves.
  • Greater occipital nerve is a branch of posterior ramus of C2, third occipital nerve is a branch of posterior ramus of C3.
• GALO is my GOTO

Question 5

The occipitofrontalis muscle is
innervated by ______

Answer 5

The occipitofrontalis muscle is a muscle of facial expression and is therefore
innervated by the facial nerve (CN VII).

Question 6

Branches of ophthalmic artery (supratrochlear and supra-orbital) supply ____ and ______ aspects of scalp.

Branches of external carotid artery (superficial temporal, posterior auricular, and occipital) supply ______ and ______ aspects of scalp.

Answer 6

Branches of ophthalmic artery (supratrochlear and supra-orbital) supply anterior and superior aspects of scalp.

Branches of external carotid artery (superficial temporal, posterior auricular, and occipital) supply lateral and posterior aspects of scalp.

Question 7

Describe the Lymphatic drainage of the scalp

Answer 7

Lymphatic drainage of the scalp generally follows the pattern of arterial distribution.

• Lymphatics in _occipital regio_n initially drain to occipital nodes, then drain into upper deep cervical nodes (with some direct drainage).

Question 8

If you’re suturing the skin, where should you put the anaesthetics?

Answer 8

If the area is Anterior to Ears and the Vertex, anaethetise the area just anterior to the laceration

If the area is Posterior to Ears and the Vertex, anaethetise the area just posterior to the laceration

If the area is lateral, anaesthetise the area just below the laceration

(think of how the nerves run)

Question 9

What are the names of the groups of muscles of facial expression

Answer 9

Muscles Of Facial Expression (Not Expected To Know All Facial Muscles But Need To Know Groups)

Muscles of facial expressions lie in superficial fascia, originating from either bone or fascia and inserting to skin. All facial muscles are innervated by facial nerve (VII).

The muscles are grouped in 1) orbital, 2) nasal, 3) oral and 4) other groups.

Important muscles to know include orbicularis oculi; buccinators, upper and lower lip muscles (e.g. orbicularis oris); platysma, occipitofrontalis, auricularis.

Question 10

Name some important muscles of facial expression (7)

Answer 10

Important muscles to know include orbicularis oculi; buccinators, upper and lower lip muscles (e.g. orbicularis oris); platysma, occipitofrontalis, auricularis.

Question 11

Describe the Two muscles associated with orbital group

Answer 11

1) Orbicularis Oculi

Orbicularis oculi is a large muscle that surrounds each orbital orifice and extends into each eyelid. It closes the eyelids.

• It has two major parts, which are outer orbital part (closes eye more forcefully) and inner palpebral part (closes eye gently)
• Additional small lacrimal part attaches to bone posterior to lacrimal sac of lacrimal apparatus.

2) Corrugator Supercilii

• ​The corrugator draws the eyebrow downward and medially, producing the vertical wrinkles of the forehead. It is the “frowning” muscle, and may be regarded as the principal muscle in the expression of suffering.

Question 12

Describe the muscles in the oral group

Answer 12

• Muscles in oral group move lips and cheek, includings orbicularis oris, buccinators muscles, lower and upper group of muscles

Many muscles intersect lateral to modiolus (corner of mouth).

• Orbicularis oris is a complex muscle completely encircle the mouth.
  
  • Its function is to narrows mouth and closes lips, e.g. whistling.
• Buccinator forms muscular component of cheek (lateral part of oral cavity).
  
  • Its function is pressing cheek against teeth, forceful expulsion of air from cheeks.
  • Fibers of buccinator pass toward modiolus to insert into lips, blending with orbicularis oris.
• Muscles of lower oral group consist of depressor anguli oris, depressor labii inferioris. and mentalis (learn function not names)
  
  • It depresses modiolus, depresses/raise lower lip (drinking).
• Muscles of upper oral group consist of risorius, zygomaticus major, zygomaticus minor, levator labii superioris, levator labii superioris alaeque nasi, and levator anguli oris. (learn function not names)
  
  • It elevates modiolus (smile), deepen sadness, nasal flaring (nostril widen breathing).

Question 13

Muscles in oral group move ____ and ____

Answer 13

Muscles in oral group move lips and cheek, includings orbicularis oris, buccinators muscles, lower and upper group of muscles

Question 14

What is the 1 muscle we need to know for the Nasal Group?

Answer 14

Three muscles are associated with the nasal group, including nasalis, procerus, and depressor septi nasi. (don’t need to know the last 2)

Question 15

What other muscles (aside from those in the oral, nasal and orbital group) are involved in muscles o facial expression?

Answer 15

Platysma is a large, thin sheet of muscle in the superficial fascia of the neck.

• It tenses neck skin and depresses lower lip and modiolus.

Auricular muscles are associated with ears, including anterior, superior, and posterior auricularis.

Occipitofrontalis is associated with scalp.

• It consists of a frontal belly anteriorly and occipital belly posteriorly. It has an aponeurotic tendon connecting two bellies.
• It moves scalp and wrinkle the forehead.

Question 16

Describe the Sensory Innervation of the FACE

Answer 16

(most are branches off the trigeminal nerve V)

Because face is derived developmentally from first pharyngeal arch, cutaneous innervation of the face is mostly by branches of trigeminal nerve (V), which are ophthalmic (V1), maxillary (V2) and mandibular (V3) nerve.

• Ophthalmic nerve (V1) exits through superior orbital fissure, branches into supra-orbital, supratrochlear, infratrochlear, lacrimal, external nasal nerve.
• Maxillary nerve (V2) exits through foramen rotundum, branches into zygomaticotemporal and zygomaticofacial branches (small), i_nfra-orbital nerve_ (large).
• Mandibular nerve (V3) exits through foramen ovale, branches into auriculotemporal, buccal, mental nerve.

The exception is a small area covering the angle and lower border of ramus of mandible and parts of the ear, where facial (VII), vagus (X) and cervical nerves contribute to the innervation.

Question 17

Ophthalmic nerve (V1) exits through _______, branches into______

Answer 17

Ophthalmic nerve (V1) exits through superior orbital fissure, branches into supra-orbital, supratrochlear, infratrochlear, lacrimal, external nasal nerve.

Question 18

Maxillary nerve (V2) exits through ______, branches into ________

Answer 18

Maxillary nerve (V2) exits through foramen rotundum, branches into zygomaticotemporal and zygomaticofacial branches (small), infra-orbital nerve (large).

Question 19

Mandibular nerve (V3) exits through ________, branches into ________

Answer 19

Mandibular nerve (V3) exits through foramen ovale, branches into auriculotemporal, buccal, mental nerve.

Question 20

What innervates the front part of the neck?

Answer 20

Neck = Cervical plexus

Anterior = Transverse cervical

Question 21

Describe the Position of the Parotid Gland

Answer 21

Parotid gland is the largest of the three pairs of the salivary glands.

Facial nerve (V) runs through gland.

It _wraps around mandible (superficial, posterior and deep), sits o_ver ramus of mandible and masseter muscle.

• Superficial:
  
  • It lies anterior and just below ear.
  • Superficial part lies on top of ramus.
  • Sits below the zygomatic arch
  • How far it comes anteriorly defers from individual to individual
• Deep:
  
  • It wraps around the ramus and goes deep to the ramus
  • Deep part goes right at back of ramus.

Question 22

Describe Sensory innervation of the parotid gland and the parotid fascia

Answer 22

_Sensory i_nnervation of parotid gland is provided by auriculotemporal nerve, which is a branch of mandibular nerve (V3).

As soon as trigeminal or inferior mandibular nerve comes into infratemporal fossa, it gives a branch called auriculotemporal nerve.

Sensory innervation of parotid fascia is provided by great auricular nerve (C2).

Question 23

_Sensory i_nnervation of parotid gland is provided by _____nerve, which is a branch of______. As soon as trigeminal or inferior mandibular nerve comes into infratemporal fossa, it gives a branch called auriculotemporal nerve.

Sensory innervation of parotid fascia is provided by _______\_

Answer 23

_Sensory i_nnervation of parotid gland is provided by auriculotemporal nerve, which is a branch of mandibular nerve (V3). As soon as trigeminal or inferior mandibular nerve comes into infratemporal fossa, it gives a branch called auriculotemporal nerve.

Sensory innervation of parotid fascia is provided by great auricular nerve (C2).

Question 24

Describe the Autonomic Innervation of the Parotid gland

Answer 24

Parasympathetic (secretomotor) fibres to gland come from two sources, which are glossopharyngeal (IX) (main) (preganglionic parasympathetic) and auriculotemporal (V3) (postganglionic parasympathetic).

Sympathetic fibres comes from superior cervical ganglion via external carotid artery and middle meningeal artery.

Question 25

Describe the Position of the Parotid Duct

Answer 25

Parotid gland d_rains its salivary secretions_ to mouth by parotid duct. * Parotid duct (Stensen duct) leaves anterior border of gland midway between zygomatic arch and mouth modiolus. * It crosses face in a transverse course over masseter muscle. It is very superficial, right under skin (within 2mm). * At anterior border of masseter muscle, it turns deeply (90°) into buccinator fat and pierces buccinator muscle to enter oral cavity. It _opens into oral cavity near the second upper molar tooth._

Question 26

Parotid gland drains its salivary secretions to mouth by \_\_\_\_\_\_

Answer 26

Parotid gland drains its salivary secretions to mouth by parotid duct.

Question 27

Describe the Surface Anatomy of the Parotid Duct

Answer 27

Surface anatomy of parotid duct is important when assessing f_acial lacerations_ and in facial reconstruction surgery. * If only skin is sutured up, patient may come back with a fistula whenever they have lunch or dinner, so s_aliva running down the face._* * Surface anatomy of parotid duct has been recently revisited. It is most accurately represented by _middle half of a line between lower border of tragus and cheilion_. In more than 90% of individuals, it runs within 1_.5cm of this line_

Question 28

What is the tragus?

Answer 28

The tragus is a small pointed eminence of the external ear, situated in front of the concha, and projecting backward over the meatus.

Question 29

Where is the cheilion?

Answer 29

Corner of mouth

Question 30

Describe the branches of the Facial Nerve

Answer 30

Facial nerve exits the skull through _stylomastoid foramen_ and then passes into _parotid gland_, where it usually divides into _upper and lower trunks_. _Five terminal groups_ of branches (_temporal_, _zygomatic_, _buccal_, _marginal_ _mandibular_, _cervical_) emerge from parotid gland. * Upper: Temprozygotmatic * Temporal * Zygotmatic * Buccal * Lower: Cervicofacial * Marginal mandibular (danger of damage when trying to remove skin cancer) * Cervical Intimate relationships between facial nerve and parotid gland mean surgical removal of parotid gland is a difficult dissection. * Facial nerve runs between mastoid process and styloid process, penetrates parotid gland between the superficial and deep parts and then crosses superficial to the retromandibular vein, external carotid artery (runs within the tissue), mandible and the masseter muscle. * In dissection, if you are going from an anterior approach, and if you see veins and artery, it means you crossed the nerve.

Question 31

Facial nerve exits the skull through _______ and then passes into \_\_\_\_\_\_, where it usually divides into upper and lower trunks. Five terminal groups of branches\_\_\_\_\_\_\_\_\_\_\_\_\_\_ emerge from the parotid gland.

Answer 31

Facial nerve exits the skull through _stylomastoid foramen_ and then passes into _parotid gland,_ where it usually divides into upper and lower trunks. Five terminal groups of branches (1) **temporal**, 2) **zygomatic**, 3) **buccal**, 4) **marginal** **mandibular**, 5) **cervical**) emerge from parotid gland. * Upper: Temprozygotmatic * Temporal * Zygotmatic * Buccal * Lower: Cervicofacial * Marginal mandibular (likely to be damaged in skin cancer) * Cervical

Question 32

Describe the sensory innervation to the parotid gland

Answer 32

Sensory innervation is provided by the auriculotemporal nerve, which is a branch of the **mandibular nerve (CN V3)**. The secretomotor fibres to the gland come from two sources; **CN V3** (postganglionic parasympathetic) and **CN IX** (preganglionic parasympathetic).

Question 33

Describe the Relations between the facila nerve and the parotid gland

Answer 33

Intimate relationships between _facial nerve_ and _parotid gland_ mean surgical removal of parotid gland is a difficult dissection. * Facial nerve runs between _mastoid process and styloid process,_ penetrates _parotid gland_ between the superficial and deep parts and then crosses superficial to the r_etromandibular vein_, _external carotid artery_ (runs within the tissue), _mandible_ and the _masseter_ muscle. * In dissection, if you are going from an anterior approach, and if you see _veins_ and _artery_, it means you _crossed the nerve._

Question 34

The muscles of facial expressions lie in the \_\_\_\_\_\_\_\_\_\_ originating from either \_\_\_\_\_\_or \_\_\_\_\_\_\_and inserting to the \_\_\_\_\_\_. They all are innervated by the \_\_\_\_\_\_

Answer 34

The muscles of facial expressions lie in the **superficial fascia** originating from either bone or fascia and **inserting to the skin.** They all are innervated by the **facial nerve (CN VII).**

Question 35

Describe how to facial nerve runs

Answer 35

The facial nerve exits the skull through the s**tylomastoid foramen** and immediately gives off the **_posterior auricular nerve (1)_** that passes back and up to supply the occipital part of occipitofrontalis. The next branch, which comes off the facial nerve, is to supply the posterior belly of **digastric (2)** and **stylohyoid muscles (A**). The facial nerve then enters the posteromedial surface of the parotid gland and divides into an upper **temporozygomatic (3**) and **lower cervicofacial (4)** branch. The branching pattern of the facial never is variable as it runs through the superficial part of the parotid gland. Five branches eventually emerge from the anterior border of the parotid gland; the _temporal_, _zygomatic_, _buccal_, _marginal_ _mandibular_ and the _cervical_ branches (B).

Question 36

What areas do each of the branches of the facial nerve innervate?

Answer 36

Temporal branch – Innervates the frontalis, orbicularis oculi and corrugator supercilii Zygomatic branch – Innervates the orbicularis oculi. Buccal branch – Innervates the orbicularis oris, buccinator and zygomaticus muscles. Marginal Mandibular branch – Innervates the mentalis muscle. Cervical branch – Innervates the platysma. - The **temporal branch** supplies the anterior and superior auricularis muscle and crosses the zygomatic arch to innervate frontalis. - The **zygomatic branch** also crosses the zygomatic arch and runs toward the corner of the eye to supply frontalis, orbicularis oculi and muscles below the eye (paralysing impairs blinking). - The **buccal branch s**upplies buccinator and muscles of the upper lip. - The **marginal mandibular branch** supplies the muscles of the lower lip after travelling along the lower border of the mandible. - The **cervical branch** supplies platysma. The Zebra Baked My Cake

Question 37

Describe the relations between the facial nerve and the parotid gland

Answer 37

The facial nerve is in close relations with several important structures within the parotid gland and being aware of these relations is surgically important. The facial nerve runs between the mastoid process and the styloid process, penetrates the parotid gland between the superficial and deep parts and then crosses superficial to the retromandibular vein, external carotid artery, mandible and the masseter muscle.

Question 38

Describe the Surface anatomy of the partoid duct

Answer 38

The surface anatomy of the parotid duct is important when assessing _facial lacerations_ and in _facial reconstruction surgery._ The surface anatomy of the parotid duct has been recently revisited. It is most accurately represented by the _middle half of a line_ between _lower border of tragus and cheilion._ In more than 90% of individuals _it runs within 1.5cm of this line_

Question 39

The ______ and \_\_\_\_\_\_mandibular branches of the facial nerve are very vulnerable to injury during surgical procedures

Answer 39

The **temporal** and **marginal** mandibular branches of the facial nerve are very vulnerable to injury during surgical procedures (e.g. biopsies of skin cancers) and traumatic lacerations due to its superficial course and variable distribution. It is important to know the surface anatomy of the facial nerve

Question 40

What nerves supply the skin of the neck?

Answer 40

Lesser occipital nerve (C2) Greater auricular nerve (C2/3) Transverse cervical nerve (C2/3) Supraclavicular nerve (C3/4)

Question 41

What nerves supply the skin of the head?

Answer 41

(See 10/11) Trigeminal - Opthamic division) *