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