Lecture 10 and (11?): Face and Parotid Flashcards
What is the Scalp?
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.
What are the 5 layers of the Scalp?
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.
Describe the Blood supply and the venous drainage of the Scalp
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
Describe the Nerve supply to the scalp
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
The occipitofrontalis muscle is
innervated by ______
The occipitofrontalis muscle is a muscle of facial expression and is therefore
innervated by the facial nerve (CN VII).
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.
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.
Describe the Lymphatic drainage of the scalp
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).
If you’re suturing the skin, where should you put the anaesthetics?
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)
What are the names of the groups of muscles of facial expression
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.
Name some important muscles of facial expression (7)
Important muscles to know include orbicularis oculi; buccinators, upper and lower lip muscles (e.g. orbicularis oris); platysma, occipitofrontalis, auricularis.
Describe the Two muscles associated with orbital group
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.
Describe the muscles in the oral group
- 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).
Muscles in oral group move ____ and ____
Muscles in oral group move lips and cheek, includings orbicularis oris, buccinators muscles, lower and upper group of muscles
What is the 1 muscle we need to know for the Nasal Group?
Three muscles are associated with the nasal group, including nasalis, procerus, and depressor septi nasi. (don’t need to know the last 2)
What other muscles (aside from those in the oral, nasal and orbital group) are involved in muscles o facial expression?
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.
Describe the Sensory Innervation of the FACE
(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.
Ophthalmic nerve (V1) exits through _______, branches into______
Ophthalmic nerve (V1) exits through superior orbital fissure, branches into supra-orbital, supratrochlear, infratrochlear, lacrimal, external nasal nerve.
Maxillary nerve (V2) exits through ______, branches into ________
Maxillary nerve (V2) exits through foramen rotundum, branches into zygomaticotemporal and zygomaticofacial branches (small), infra-orbital nerve (large).
Mandibular nerve (V3) exits through ________, branches into ________
Mandibular nerve (V3) exits through foramen ovale, branches into auriculotemporal, buccal, mental nerve.
What innervates the front part of the neck?
Neck = Cervical plexus
Anterior = Transverse cervical
Describe the Position of the Parotid Gland
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.
Describe Sensory innervation of the parotid gland and the parotid fascia
_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).
Describe the Position of the Parotid Duct
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.
Describe the Surface Anatomy of the Parotid Duct
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
What is the tragus?
The tragus is a small pointed eminence of the external ear, situated in front of the concha, and projecting backward over the meatus.
Where is the cheilion?
Corner of mouth
Describe the Relations between the facila nerve and the parotid gland
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.
Describe the relations between the facial nerve and the parotid gland
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.
Describe the Surface anatomy of the partoid duct
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
