What makes up the roof of the oral cavity?
The hard palate
What makes up the floor of the oral cavity?
The tongue and other soft tissues
WHat forms the lateral walls of the oral cavity?
The cheeks
What forms the anterior boundary of the oral cavity?
The oral fissure
What forms the posterior boundary of the oral cavity?
The oropharyngeal isthmus
What is the oral vestibule?
The space between the cheeks/lips and teeth
What defines the oral cavity proper?
Teeth -> ring made by palatopharangeal arch, uvula, tip of epiglottis
What is the palatoglossal arch?
Curve from tonsil to uvula AKA anterior arch
What is the platopharyngeal arch?
AKA posterior arch, located behind palatoglossal arch
What is the hard palate?
Roof of oral cavity, formed from maxilla and palatine bones
Which bones conrtibute to the floor of the oral cavity?
Maxilla and palatine
What is the soft palate?
Muscular tissue that forms the posterior part of the roof of the oral cavity
What is the function of the soft palate?
Tenses to elevate during yawning and swallowing
Which nerve innervates the muscles of the soft palate?
Vagus predominantly, pharyngeal branch.
If damaged the stronger side is unopposed so uvula pulls away from affected side
Which two nerves are involved in the gag refelx and how?
Glossopharyngeal on afferent limb (back of throat area)
Vagus on efferent (pharyngeal muscles of soft palate)
Name the teeth from back to front of the mouth
3rd to 1st molar 2nd to 1st premolar Canine Lateral incisor Central incisor
What is the sensory supply to the lower jaw?
Inferior alveolar nerve CN V3
Sensation can be lost in mandibular fracture
How many extrinsic muscles of the tongue are there? What are they called?
4 - all "glossus" endings Styloglossus Hyoglossus Genioglossus Palatoglossus
What is the main function of the extrinsic muscles of the tongue?
Anchoring of the tongue to the hyoid bone and mandible
How many intrinsic muscles of the tongue are there? Names?
5 Superior longitudinal Vertical Transverse Inferior longitudinal Septum
What is the function of the intrinsic muscles of the tongue?
Help tongue to change shape. Actions based on direction of fibres
Which nerve innervates the majority of the muscles of the tongue?
Hypoglossal nerve (glossus) CN XII
Which muscles of the tonuge are not innervated by the hypoglossal nerve?
Only Palatoglossus
Which way does the tongue deviate when a nerve is not functioning properly?
Towards the affected side i.e. normal muscle overpowers weaker one
How does the parotid gland enter the oral cavity?
Single opening - Stenson’s Duct
How does the submandibular gland enter the oral cavity?
Single opening - Wharton’s duct
How does the sublingual gland enter the oral cavity?
Multiple ducts
Describe salivary gland stones
Usually calcium-based
The result of crystallisation of saliva in ducts
Which gland most commonly suffers from salivary stones and why?
Submandibular duct (Wharton's) Produces comparatively thicker slaiva
What is the common presentation of salivary gland stones?
Pain or swelling of affected gland at meal times
How are salivary stones treated?
Small stones may resolve spontaneosuly, otherwise they can be removed
What is tonsilitis?
Inflammation of the palatine tonsil
How does tonsilitis present?
Sore throat
Odynophagia (pain on swallowing)
Dysphagia
Tonsils are tyoically elarged and erythematous
What causes tonsilitis?
Usually infective
Viral e.g. rhinovirus, adenovirus
Bacterial e.g. beta haemolytic strep
What additional symptoms are seen in viral tonsilitis?
Those of a URTI e.g. dry cough
What additional symptoms are seen in bacterial tonsilitis?
Cervical lymphadenopathy
Fever
Pus
In terms of arches, what occurs during tonsilitis?
The posterior arch disappears
What is Quinsy?
Peritonsillar abscess as a complication of bacterial tonsilitis
What are the common organisms involved in Quinsy?
Strep pyogenes
Staph Aureus
H. influenza
What are the symptoms of Quinsy?
Systemically unwell
Trismus, or “hot potato voice”
Dysphagia +/- drooling
Describe the temporomandibular joint
Modified hinge, synovial, between the cranium and mandible
Specify the articulation point of the TMJ
Condyle of mandible with articular tubercle of temporal bone (in mandibular fossa)
Name the ligaments of the TMJ
Hint: 3
Lateral or temporomandibular ligament
Stylomandibular
Sphenomandibular
Which muscles elevate the mandible?
Hint: 3
Temporal, masseter, medial pterygoid
Which muscles depress the mandible?
Hint: 3
Lateral pterygoid, supr/infra hyoid
Which musle(s) is/are used in protrusion of the mandible?
Lateral pterygoid
Which musle(s) is/are used in retrusion of the mandible?
Temporal
Which muscles are involved in lateral movement of the mandible?
Hint: 3
Temporal on same side
Pterygoids of opposite side
Masseter
Which muslces are involved in mastication? What nerve supplies them all? Hint: 3
Temporalis, masseter, pterygoids
Mandibular branch of trigeminal nerve CN V3
How is the TMJ dislocated?
Sideways blow to chin when mouth open
Anatomically speaking, what happens when the TMJ dislocates?
Movement of head of mandible anteriorly to articular tubercle
List some other TMJ disorders
Bruxism
Osteoarthritis
Inter-articular disk derangement
What is arteritis and how can it relate to the TMJ?
Inflammation of arteries. Can cause pain around TMJ if temporal artery involved
What is the infratemporal fossa?
Irregularly shaped space deep and inferior to zygomatic arch, deep to ramus of mandible
What is the superior border of the infratemporal fossa?
Inferior greater wing of the sphenoid bone
What is the posterior border of the infratemporal fossa?
Temporal bone
What is the inferior border of the infratemporal fossa?
Point of attachement of the medial pterygoid at the mandible
What is the anterior border of the infratemporal fossa?
Posterior maxillary bone
What is the lateral border of the infratemporal fossa?
Ramus of mandible
What is the medial border of the infratemporal fossa?
Lateral pterygoid plate of sphenoid
What is the muscular content of the infratemporal fossa?
Hint: 3
Temporal muscle
Lateral and medial pterygoid muscles
Wha is the vessel content of the infratemporal fossa?
Maxillary artery
Pterygoid venous plexus (comms with cavernous sinus)
Which nerves are found in the infratemporal fossa?
Hint: 6
Mandibular Inferior alveolar Lingual Buccal Chorda tympani Otic ganglion
What does the otic ganglion supply?
Parotid gland (parasympathetically)
What is the clinical relevance of the infratemporal fossa?
Site of isolated infection
Risk of infection spreading to cavernous sinus via pterygoid plexus
Possible site of mandibular nerve blocks
Recap: What are the pharyngeal arches?
A complex tissue system making up the embryonic head and neck Involves the brain, cvs & special sensory organs
Which factors drive the development of the face?
Hint: 3
Expansion of the cranial neural tube
Developmnet of complex tissue associated with the cranial gut tube & heart outflow
The need to separate resp. and GI tracts
Recap: What is a pharyngeal arch made of?
Artery, vein, nerve
Mesenchyme filling
Ectodermal covering
Endometrial lining
How are the pharyngeal arches arranged?
Around the aortic arch vessels
What is the neural crest?
Specialised cell population originating from lateral borders of neuroectoderm
List the major features of the face
Palpebral fissures
Oral fissure
Nares
Philtrum
From where does the facial skeleton arise?
Neural crest of 1st pharyngeal arch
From where do the muscles of mastication arise?
Mesoderm of 1st pharyngeal arch
From where do the muscles of facial expression arise?
Mesoderm of 2nd pharyngeal arch
What is the frontonasal prominence (FNP)?
The area from which arises the forehead, bridge of nose, nose and philtrum
What is the maxillary prominence?
Structure giving rise to cheeks, lateral upper lip & lateral upper jaw
What is the mandibular prominence?
Structure from which the lower lip and jaw arise
Briefly describe the preliminary stages of embryonic nose development
Nasal placodes appear on FNP -> sink to become nasal pits -> medial and lateral nasal prominences form on eith side of pits
Briefly describe the latter stages of embryonic nose development
Maxillary prominences grow medially -> push nasal prominences closer to midline -> prominences fuse -> medial nasal prominences fuse in midline
What is the intermaxillary segment?
Result of fusion of medial nasal prominences
What is responsible for the separation of the nasal & oral cavities?
The development of the secondary palate, derived from the palatal shelves from the maxillary prominences
What is needed of the mandible to allow separation of the nasal and oral cavities?
Growth to a size large enough to allow tongue to drop
Describe how the lip and palate have a dual origin
They are formed from the maxillary process as well as the intermaxillary segment
What is a lateral cleft lip?
Result of failure of fusion of medial nasal prominence with maxillary prominence
What is a cleft lip and cleft palate?
Cleft lip + failure of palatal shelves to meet in midline
When does development of the eyes begin?
4th week
Describe the preliminary stages of eye development
Out-pocketings of forebrain grow out making contact with ectoderm, optic placodes form
What do optic placodes become?
Lenses
Describe the intermediate stages of embryonic eye development
Optic vesicles grow out towards surface in direction of placodes
Placode then invaginates and pinches off
From where is the retina derived?
The forebrain
How do the eye primordia move as facial prominences grow?
Side -> front (allowing binocular vision)
From where does the external auditory meatus arise?
1st pharyngeal cleft
From where do the pinnas arise?
Proliferation around teh 1st and 2nd
What is a lateral cleft lip?
Result of failure of fusion of medial nasal prominence with maxillary prominence
What is a cleft lip and cleft palate?
Cleft lip + failure of palatal shelves to meet in midline
When does development of the eyes begin?
4th week
Describe the preliminary stages of eye development
Out-pocketings of forebrain grow out making contact with ectoderm, optic placodes form
What do optic placodes become?
Lenses
Describe the intermediate stages of embryonic eye development
Optic vesicles grow out towards surface in direction of placodes
Placode then invaginates and pinches off
From where is the retina derived?
The forebrain
How do the eye primordia move as facial prominences grow?
Side -> front (allowing binocular vision)
From where does the external auditory meatus arise?
1st pharyngeal cleft
From where do the pinnas arise?
Proliferation around the 1st and 2nd
How do the ears migrate in development?
Neck -> ascend to side of head as mandible grows
What are the otic placodes?
Placodes involved in hearing
Invaginate auditory vesicles
Why is foetal alcohol syndrome significant to development?
Neural crest migration + brain development are extremely sensitive to alcohol (FAS+ARND = 1/100 births)