Region 11 - Face Flashcards
What is the structure of the parotid gland?
Serous acini ONLY
Connective tissue capsule
Dense fibrous capsule:
- Extends as stylomandibular ligament
Where does the parotid duct lie?
~1 fingers breadth below zygomatic arch
What is the course of the parotid duct?
Passes anteriorly from anterior end of gland
Turns medially at anterior end of masseter:
- Pierces buccal fat pad and bucinnator
- Enters oral cavity opposite 2nd upper molar tooth
How can the parotid gland be palpated?
If masseter is tensed
What is the parotid plexus?
The branch point of the facial nerve which lies within the parotid gland
What are the branches of the parotid plexus?
Temporal branches Zygomatic branches Buccal branches Marginal mandibular branch Cervical branch
What nerve branches from the parotid plexus between it leaving the stylomastoid foramen and before it entering the parotid gland?
Posterior auricular nerve
What are the two terminal branches of the ECA within the parotid gland?
Superficial temporal artery
Maxillary artery
What veins join to form the retromandibular vein within the parotid gland?
Superficial temporal vein
Maxillary vein
What does the facial nerve divide the parotid gland into?
Superficial part
Deep part
How do parasympathetic secretomotor fibres from the glossopharyngeal nerve reach the parotid gland?
- CN IX leaves skull through jugular foramen
- CN IX gives off tympanic branch
- Tympanic branch travels through tympanic hiatus
- Tympanic branch enters tympanic plexus
- PNS fibres enter lesser petrosal nerve
- Lesser petrosal nerve leaves through foramen ovale
- Lesser petrosal nerve enters otic ganglion
- PNS fibres synapse in otic ganglion
- Postsynaptic PNS fibres travel to parotid gland in auriculotemporal nerve (CN V3 branch)
How do sympathetic fibres reach the parotid gland?
Postganglionic SNS fibres from superior cervical ganglion travel alongside the middle meningeal artery
What is the innervation to the muscles of mastication?
Mandibular division of trigeminal nerve
What movements of the mandible are the muscles of mastication responsible for?
Elevation Depression Protrusion Retrusion Lateral sliding
What covers the temporalis muscle?
Temporal fascia
What are the proximal attachments of the temporalis muscle?
Floor of temporal fossa
Deep surface of temporal fascia
What are the distal attachments of the temporalis muscle?
(Tip and medial surface of) Coronoid process
Anterior border of ramus of mandible
What are the functions of the temporalis muscle?
Anterior and superior fibres elevate mandible
Posterior fibres retract mandible
What is the innervation to temporalis?
Deep temporal nerves (x2) from anterior trunk of CN V3
What are the origins of masseter?
Maxillary process of zygomatic arch
Zygomatic arch
What are the insertions of masseter?
Angle and lateral surface of the ramus of the mandible
What is the function of masseter?
Elevates mandible
What is the innervation to masseter?
Masseteric nerve from anterior trunk of CN V3
What are the origins of lateral pterygoid?
Upper head:
- Infratemporal surface of the greater wing of sphenoid
Lower head:
- Lateral surface of lateral pterygoid plate (sphenoid)
What are the insertions of lateral pterygoid?
Upper head:
- Joint capsule and articular disc of TMJ
Lower head:
- Neck of condyloid process of mandible
What are the functions of the lateral pterygoid?
Acting bilaterally: - Protracts mandible - Depresses mandible Acting unilaterally: - Swings jaw to contralateral side - Lateral chewing movements (with medial pterygoid)
What is the innervation to lateral pterygoid?
Nerve to lateral pterygoid from anterior division of CN V3
What are the origins of medial pterygoid?
Superficial head: - Tubercle of maxilla Deep head: - Medial surface of lateral pterygoid plate (- Pyramidal process of palatine bone)
What is the insertion of the medial pterygoid?
Medial surface of the angle of the mandible
What is the function of medial pterygoid?
Elevates mandible (with masseter) Lateral chewing movements (with lateral pterygoid)
What is the innervation to medial pterygoid?
Nerve to medial pterygoid from main trunk of CN V3
What movements occur at the TMJ during elevation of the mandible?
Head of mandible and disc move backwards
Head of mandible rotates on lower surface of disc
What muscles are involved in elevation of mandible?
Temporalis
Masseter
Medial pterygoid
What movements occur at the TMJ during depression of the mandible?
Head of mandible rotates on undersurface of disc
Mandible pulled forward
What muscles are involved in depression of the mandible?
Lateral pterygoid Digastric Geniohyoid Mylohyoid (Gravity)
What movements occur at the TMJ during protrusion of the mandible?
Disc and head of mandible move forward
Movement in upper part of cavity
What muscles are involved in protrusion of the mandible?
Lateral pterygoid:
- Assisted by medial pterygoid
What movements occur at the TMJ during retrusion of the mandible?
Disc and head of mandible pulled backwards into mandibular fossa
What muscles are involved in retrusion of the mandible?
Temporalis (posterior fibres)
How is lateral chewing carried out?
Protrusion and retrusion of the mandible combined
What muscles are involved in lateral chewing?
Lateral pterygoid
Medial pterygoid
Where do the sensory and motor branches of CN V3 unite?
After the nerves pass through the foramen ovale
What are the branches of CN V3 from its main trunk (ie pre-division)?
Meningeal branch
Nerve to medial pterygoid (which also supplies):
(- Tensor tympani)
(- Tensor veli palatini)
What are the motor branches of the anterior division of CN V3?
Masseteric nerve
Nerve to lateral pterygoid
Deep temporal nerves (x2)
What are the sensory branches of the anterior division of CN V3?
Buccal nerve:
- Skin of cheek
- Mucous membrane of mouth
What are the sensory branches of the posterior division of CN V3?
Auriculotemporal nerve: - Scalp - Auricle - TMJ - EAM - Tympanic membrane Lingual nerve: - Floor of mouth - Anterior 2/3 of tongue (general sensory)
What are the dual motor and sensory branches of the posterior division of CN V3?
Inferior alveolar nerve: - Lower teeth - Skin Mylohyoid nerve: - Mylohyoid - Anterior belly of digastric
What ganglion does the nerve to medial pterygoid pass through?
Otic ganglion
What does the medial pterygoid nerve supply via the otic ganglion?
Tensor veli palatini
Tensor tympani
What does the auriculotemporal branch of CN V3 act as a carrier for?
Postganglionic PNS fibres from otic ganglion to parotid gland
What nerves joins the lingual branch of CN V3?
Chorda tympani
What fibres does the lingual nerve carry that originate from CN VII?
PNS fibres in chorda tympani to:
- Submandibular gland
- Sublingual glands
Taste from anterior 2/3 of tongue
Where does the external carotid artery terminate?
Behind neck of mandible
What are the terminal branches of the ECA?
Maxillary artery
Superficial temporal artery
What is the occipital branch of the ECA crossed by?
CN XII
What is the course of the occipital artery?
Posterior branch of ECA
Close to origin of facial artery
Passes under posterior belly of digastric:
- Into posterior triangle of neck
What does the occipital artery supply?
Back of scalp
What is the course of the posterior auricular artery?
Posterior branch of ECA
Arises at level of upper border of belly of digastric
What does the posterior auricular artery supply?
Scalp
Where does the ascending pharyngeal artery ascend?
Between:
- ICA
- Pharynx
Where does the ascending pharyngeal artery arise?
From deep/medial surface of ECA
What is the course of the superior thyroid artery?
1st anterior branch of ECA near origin
Runs with external laryngeal nerve
What does the superior thyroid artery gives branches to supply?
SCM
Superior laryngeal artery
What is the course of the lingual artery?
2nd anterior branch of ECA:
- Arises opposite tip of greater cornu of hyoid
Passes deep to hyoglossus
What crosses the lingual artery?
CN XII
What does the lingual artery supply?
Oral cavity
What is the course of the facial artery?
3rd anterior branch of ECA:
- Arises above tip of greater cornu of hyoid
Passes deep to posterior belly of digastric
What are the branches of the facial artery?
Superior and inferior labial arteries Angular artery (to face)
What is the course of the superficial temporal artery?
Smaller terminal branch of ECA
Ascends anterior to auricle
What branch does the superficial temporal artery give off?
Transverse facial artery
What does the superficial temporal artery supply?
Skin over frontal and temporal regions via anterior and posterior branches`
Where does the maxillary artery arise?
Terminal branch of ECA behind neck of mandible
What does the maxillary artery supply?
Muscles of mastication Tympanic membrane Upper and lower teeth Palate Nasal cavity Nasopharynx Meninges
What is the infratemporal fossa?
A ‘space’ between the base of the skull between:
- The skull AND
- The ramus of mandible
What are the boundaries of the infratemporal fossa?
Anterior = Posterior surface of maxilla Posterior = Styloid (and mastoid) process of temporal bone Superior = Infratemporal surface of greater wing of sphenoid Inferior = Medial pterygoid attachment to mandible Medial = Lateral pterygoid plate of sphenoid Lateral = Ramus of mandible
What are the contents of the infratemporal fossa?
Lateral and medial pterygoids CN V3 and its branches Maxillary artery and its branches Pterygoid venous plexus Chorda tympani Otic ganglion
What are the branches from the superior aspect of the mandibular part of the maxillary artery?
Deep auricular artery
Anterior tympanic artery
Middle meningeal artery
Accessory meningeal artery
What is the branch from the inferior aspect of the mandibular part of the maxillary artery?
Inferior alveolar artery:
- Branch to mylohyoid
- Inferior alveolar artery proper
What are the branches from the superior aspect of the pterygoid part of the maxillary artery?
Masseteric artery
Deep temporal branches (x2)
What are the branches from the inferior aspect of the pterygoid part of the maxillary artery?
Pterygoid branch
Buccal branch
What are the branches of the pterygopalatine part of the maxillary artery?
Posterior superior alveolar artery Infraorbital artery Anterior superior alveolar branches Palatine artery Pharyngeal artery Sphenopalatine artery
What does the pterygoid venous plexus surround?
Lateral pterygoid
What veins contribute to the pterygoid venous plexus?
Veins from:
- Orbit
- Nasal cavities
- Oral cavity
What does the pterygoid venous plexus communicate with?
Cavernous sinus
Facial vein
What drains the pterygoid venous plexus?
Maxillary vein
What is the clinical implication of the pterygoid venous plexus?
Route for infection
In what ganglion do the various fibres of the facial nerve coalesce?
Geniculate ganglion
What are the functions of the chorda tympani branch of CN VII?
PNS fibres (secretomotor) to: - Submandibular salivary gland - Sublingual salivary glands Taste from anterior 2/3 of tongue
What nerve carries the fibres from the chorda tympani to its destinations?
Lingual nerve (branch of CN V3)
What are the PNS fibre contents of the otic ganglion?
Synapse of fibres from lesser petrosal nerve onto postganglionic fibres in auriculotemporal nerve
What are the SNS fibre contents of the otic ganglion?
Postganglionic vasomotor fibres:
- Then travel via auriculotemporal nerve
What are the motor fibre contents of the otic ganglion?
CN V3 branches to:
- Tensor tympanic
- Tensor veli palatini
(Do not synapse in ganglion)
What is the joint of the TMJ between?
Head of mandible inferiorly
AND
Mandibular fossa and articular tubercle of squamous temporal bone superiorly
What are the articular surfaces of the TMJ covered in?
Fibrocartilage articular disc of the TMJ
What surrounds the TMJ?
Fibrous capsule
What is the nerve supply to the TMJ?
Auriculotemporal nerve (immediately in front) Masseteric nerve
What reinforces the joint capsule of the TMJ laterally?
Lateral (temporomandibular) ligament
What reinforces the joint capsule of the TMJ medially?
Sphenomandibular ligament
Stylomandibular ligament
What is the function of the articular disc of the TMJ?
Increases congruity of articular surfaces
Divides joint cavity into superior and inferior parts
What movements are possible between the head of the mandible and the articular disc?
Elevation and depression:
- Of mandible
- Acts as a hinge
What movements does the articular disc and the mandibular fossa permit?
Protrusion and retrusion:
- Of mandible
- Gliding movements
What movements of the mandible close the mouth?
Elevation and retraction:
- Pull the condyle backwards
What movements of the mandible open the mouth?
Depression and protrusion:
- At both sides
- Slide disc and condyle forwards towards tubercle
What does asynchronous gliding of both TMJs allow?
Chewing
What does the fascia in the scalp blend with and extend into?
Blends with superficial fascia in neck posteriorly
Extends into temporal regions laterally
What is the parotid fascia a layer of?
Deep cervical fascia
What does the parotid fascia cover and invest?
Covers masseter
Invests parotid gland
What are the origins and insertions of the muscles of facial expression?
Most originate on facial bones
Most insert into the skin/connective tissue of the face
What can the frontalis muscle also be considered?
The anterior belly of occipitofrontalis
What are the functions of frontalis?
Helps express suprise or curiosity:
- Elevates eyebrows
- Wrinkles skin of forehead
What are the functions of corrugator supercilli?
Helps express concern or worry:
- Draws eyebrows medially and inferiorly
- Creates vertical wrinkles over nose
What are the functions of platysma?
Conveys tension and stress:
- Tenses skin of lower face and neck
(Also depresses mandible)
What are the functions of procerus PLUS transverse part of nasalis?
Conveys disdain or dislike:
- Depresses medial end of eyebrow
- Wrinkles skin over dorsum of nose
What are the functions of the alar part of nasalis PLUS levator labii superioris alaeque nasii?
During anger or exertion:
- Depresses ala laterally = Flaring of nostrils
What is the function of buccinator acting alone?
Sucks in cheeks
What are the function of orbicularis oris acting alone?
Pouts lips (kissing):
- Compresses lips
- Protrudes lips
What is the function of buccinator PLUS orbicularis oris?
Puffs out cheeks (such as when blowing out air)
What are the functions of orbicularis oculi?
Closes eyes:
- Palpebral part does so gently
Winking:
- Orbital part closes eyelids tightly
What are the functions of zygomaticus major and minor?
Displaying sneering and disdain:
- Elevates corner of mouth (unilaterally)
What do the ‘dilators’ of the mouth work together to do?
To show a full ‘teethy’ smile
What are the ‘dilators’ of the mouth?
Levator labii superioris Levator anguli oris Risorius Depressor labii inferioris Depressor anguli oris
What is the function of depressor anguli oris?
Frowning (sadness):
- Depresses angle of mouth bilaterally
What are the functions of mentalis?
Elevates lower lip
Protrudes lower lip
What does the facial nerve traverse?
Internal acoustic meatus
What are the branches of the facial nerve within the temporal bone?
Greater petrosal nerve
Nerve to stapedius
Chorda tympani
How does the facial nerve leave the cranium?
Stylomastoid foramen
What does the facial nerve have the longest course of?
Longest intra-osseous course of any cranial nerve
What is the motor supply of the posterior auricular branch of CN VII?
Occipitalis
Posterior belly of digastric
Stylohyoid
What is the motor supply of the temporal branch of CN VII?
Frontalis
Orbicularis oculi
What is the motor supply of the zygomatic branch of CN VII?
Orbicularis oculi
What is the motor supply of the buccal branch of CN VII?
Zygomaticus major and minor Levator labii superioris Levator anguli oris Buccinator Orbicularis oris Nasalis
What is the motor supply of the marginal mandibular branch of CN VII?
Depressor anguli oris
Depressor labii inferioris
Mentalis
What is the motor supply of the cervical branch of CN VII?
Platysma
What are the branches of the facial artery?
Submental
Superior and inferior labial
Lateral nasal
(Continues as angular artery)
Where does the superficial temporal artery give off the transverse facial artery?
When it runs within the parotid gland
From what artery does the mental artery arise?
Inferior alveolar artery
What are the terminal branches of the ophthalmic artery?
Supra-orbital artery
Supratrochlear artery
Into what vein do the supra-orbital and supratrochlear veins drain to? Where?
Angular vein:
- Root of nose
What does the angular vein continue as? Where?
Facial vein:
- At inferior margin of orbit
Where does the facial vein drain to?
Joins anterior division of retromandibular vein:
- Forms common facial vein
- Which then drains into IJV
What is the drainage pattern of the superficial temporal vein?
Joins maxillary vein to form retromandibular vein:
- Anterior division joined by facial vein
- Posterior division joins posterior auricular vein to form external jugular vein
What are the layers of the scalp (from external to internal)?
S = Skin C = Connective tissue A = Aponeurosis (of occipitofrontalis) L = Loose areolar connective tissue P = Periosteum (pericranium)
What branches of the internal carotid artery supply the scalp?
Ophthalmic:
- Supratrochlear artery
- Supra-orbital artery
What branches of the external carotid artery supply the scalp?
Superficial temporal artery
Posterior auricular artery
Occipital artery
What are the emissary veins?
Communicating veins between:
- Superficial veins of scalp (in connective tissue layer)
- Dural venous sinuses
What are the clinical implications of the emissary veins?
Potential route for infection
What is the nerve supply to the scalp?
Supratrochlear and supra-orbital nerves (CN V1) Zygomaticotemporal nerve (CN V2) Auriculotemporal nerve (CN V3) Lesser occipital nerve (C1) Greater occipital nerve (C2) Third occipital nerve (C3)
What are the sensory branches of the ophthalmic nerve (CN V1)?
Frontal nerve: - Supraorbital nerve - Supratrochlear nerve Nasociliary nerve: - Lacrimal nerve
What are the sensory branches of the maxillary nerve (CN V2)?
Infraorbital nerve
Superior alveolar nerve
What are the sensory branches of the mandibular nerve (CN V3)?
Lingual nerve
Inferior alveolar nerve
Auriculotemporal nerve