HNS29 Oral Cavity, Submandibular And Sublingual Glands Flashcards
Oral cavity bony framework
- Maxilla
- Palatine bone (hard palate)
- Mandible
Maxilla, Mandible: with alveolar process for teeth attachment
Oral cavity boundaries
- Roof:
- Hard palate (soft palate is in pharynx) - Floor:
- Mylohyoid muscle (attach between mandible and hyoid) - Side walls:
- Buccinator muscle (CN7)
—> superior attachment: Maxilla (alveolar process)
—> **Pterygomaxillary ligament (extend from **Maxillary tuberosity to **Hamulus of medial pterygoid plate)
—> extend downward
—> **Pterygomandibular raphe (interdigitate with superior constrictor of pharynx, behind 3rd molar of mandible)
—> **links Pterygoid process to Mandible
—> insert into superior to posterior end of **Mylohyoid line
—> muscle continue to form **External oblique line of Mandible (up to 1st lower molar)
—> anterior fuse with **Orbicularis oris muscle - Anterior:
- Oral fissure - Posterior:
- Oropharynx
- separated from oropharynx by Anterior pillar of fauces (Palatoglossal arch)
Oropharyngeal fauces: bounded by Anterior pillar + Posterior pillar (Palatopharyngeal arch)
Oral cavity division
- Oral cavity proper
- space medial / posterior to teeth - Vestibule
- space between teeth/gum and cheek
- parotid duct opening is next to second upper molar each side
Sensory supply of oral cavity
CNV2
- Roof (Hard palate): Greater palatine nerve (posterior) + Nasopalatine nerve (anterior)
- Upper teeth: Superior alveolar nerve
CNV3
- Floor: Lingual nerve
- Cheek: Buccal nerve
- Lower teeth, chin: Inferior alveolar nerve
(Oropharynx: Pharyngeal plexus (CN9,10))
Hard palate bone components
- Maxilla (anterior)
- palatal processes - Palatine bone (posterior)
- horizontal plates
Fissure in between: Palatomaxillary suture
- Premaxilla
- fuse with hard palate during development —> problem with fusing —> cleft palate —> but cleft palate rarely separates premaxilla into 2 halves at the middle (usually right / left side)
Hard palate foramen
- Incisive foramen
- communication between nasal region and oral region
- **Nasopalatine nerve (from nasal cavity to oral cavity)
- **Greater palatine artery (from oral cavity into nasal cavity —> anastomoses with Sphenopalatine artery) - Greater palatine foramen
- between palatine and maxilla on hard palate
- Greater palatine artery
- Anterior palatine nerve (Greater palatine nerve) - Lesser palatine foramen
- perforate palatine bone
- Middle + Posterior palatine nerve (soft palate) (***Lesser palatine nerve)
Hard palate blood supply
Greater palatine artery:
Greater palatine artery (branch of Maxillary artery)
—> Greater palatine canal (with Anterior palatine nerve)
—> Greater palatine foramen
—> passes around hard palate
—> Incisive foramen
—> Nasal cavity (anastomoses with Sphenopalatine artery)
Hard palate nerve supply
- Anterior palatine nerve (from CNV2 —> Pterygopalatine ganglion)
- from Greater palatine foramen up to Incisive foramen - Nasopalatine nerve (from CNV2 —> Pterygopalatine ganglion)
- crosses nasal roof —> descend on nasal septum —> through Incisive foramen —> supply hard palate anterior to incisive foramen
***Soft palate
Aponeurosis (of tensor veli palatini) acted upon by 5 pairs of muscles
- Tensor veli palatini (CNV3)
- Levator veli palatini
- Palatopharyngeus muscle
- Palatoglossus muscle
- Muscular uvulae
- Tensor veli palatini (CNV3)
Origin:
- arise from basicranium and **lateral part of Cartilaginous part of Eustachian tube (outside of pharynx)
—> fibres converge towards base of pterygoid hamulus
—> flat tendon
—> **hooks around hamulus
—> go inside pharynx
—> becomes aponeurosis
Actions (拉開Eustachian tube):
- ***Tenses up aponeurosis —> so other muscles can act on it
- ***Pulls open cartilaginous part of Eustachian tube
Nerve supply:
- CNV3 (via nerve to medial pterygoid)
- Levator veli palatini (V shape)
Origin:
- inside Pharyngobasilar fascia
- from quadrate area on petrous part of temporal bone
- from **medial part of Cartilaginous part of Eustachian tube
—> round belly runs towards, medially, downwards (V-shaped sling)
—> insert onto **nasal (upper) surface of Palatine aponeurosis
Actions (扯起soft palate):
- Pull soft palate backwards + upwards
—> ***shutting nasopharynx from oropharynx (during swallowing)
Nerve supply:
- Pharyngeal plexus (CN10)
- Palatopharyngeus muscle (Inverted V)
Origin:
- 2 heads
- from horizontal plate of palatine bone
- from **back of Palatine aponeurosis
—> arches over lateral margin of Palatine aponeurosis
—> form **Posterior pillar of fauces
—> insert into ***Posterior border of Thyroid cartilage and Cornua
Actions (扯起pharynx):
- ***Depresses soft palate
- ***Elevates larynx and pharynx
Nerve supply:
- Pharyngeal plexus (CN10)
- Palatoglossus muscle
Origin:
- arises from **undersurface of Palatine aponeurosis
—> passes down to interdigitate with **Styloglossus (lateral tongue muscle)
—> form ***Anterior pillar of fauces
Actions:
- Sphincter of oropharyngeal fauces
- ***Raises tongue
Nerve supply:
- Pharyngeal plexus (CN10)
- Muscular uvulae
Origin:
- arises from posterior nasal spine and palatine aponeurosis
—> insert into mucous membrane of uvula
Actions:
- Shape the uvula
- ***Pull up uvula ipsilateral side
Nerve supply:
- Pharyngeal plexus (CN10)
Tongue
- Mass of muscle
- Contain mucous + serous glands
- Covered with mucous membrane
Divided into:
- Anterior 2/3: Oral cavity
- Posterior 1/3: Oropharynx
Anterior 2/3 tongue
- Thick fibrous mucous membrane (***Rough)
- Small projections: ***Papillae
—> Filiform
—> Fungiform
—> Foliate - ***NO glands on dorsum (upper surface)
- Prehencile (grabbing), for ***mastication
Posterior 1/3 tongue
- in Oropharynx, NOT in mouth
- bound by **Sulcus terminalis (後d) / **Vallate papillae (前d)
- NO papilla posterior to Vallate papillae
- Mucous membrane: Nodular appearance because of **mucous and serous glands + **Lingual tonsil (part of Waldeyer’s ring)
- **Smooth, for **swallowing
- ***Foramen caecum (just behind apex of Vallate papillae) —> remnant of thyroglossal duct (descend of thyroid gland)
***4 Lingual papillae
Anterior 2/3: 1. Filiform - conical - fur appearance - ***no taste buds (- somatosensory receptor: detect texture in food)
- Fungiform
- mushroom-shaped
- visible as red dots
- taste buds - Foliate
- posterolateral border of tongue (側面)
- serous glands
- taste buds
Posterior 1/3:
- Vallate (雖然係anterior 度, 但係當posterior tongue, ∵ innervated by ***CN9)
- V-shape
- 8-12 in number
- immediately in front of Foramen caecum and Sulcus terminalis
- taste buds
Tongue muscles
Midline septum divide tongue into halves
- 4 Intrinsic
- 4 Extrinsic
Intrinsic tongue muscles
- wholly within tongue
- no attachment to bones
- fibres in 3 planes perpendicular to each other
- Superior longitudinal fibres (前後)
- Inferior longitudinal fibres (前後)
- alongside Genioglossus
- medial to Hyoglossus - Transverse fibres (向左右延伸)
- origin: Midline fibrous septum
- insertion: 2 Sides of tongue - Vertical fibres (向下延伸)
- origin: Mucous membrane of dorsum
- insertion: 2 Sides of Lower part
Extrinsic tongue muscles
- ALL supplied by CN12 (except Palatoglossus (Pharyngeal plexus: CN10))
- Genioglossus (Genio: chin)
- front: to mandible - Hyoglossus
- down: to hyoid bone - Styloglossus
- back: to styloid process (temporal bone) - Palatoglossus
- up: to soft palate
- Genioglossus
- Fibres radiate widely
- Lateral to midline septum
Origin:
- ***Superior genial tubercle (Mandible)
Insertion:
- ***Mucous membrane (薄膜) of dorsum (upper surface) of tongue, lowest fibres go to hyoid (=/ geniohyoid muscle)
Nerve supply:
- CN12
- Hyoglossus
- Lateral to Genioglossus
Origin:
- body and length of greater horn of **Hyoid bone
—> extends as quadrilateral sheet on side of tongue
—> insert into **side of tongue (interdigitate with ***Styloglossus)
Nerve supply:
- CN12
- Palatoglossus
Origin:
- arises from **undersurface of palatine aponeurosis
—> passes down to interdigitate with **Styloglossus (lateral tongue muscle)
—> form ***Anterior pillar of fauces
Nerve supply:
- Pharyngeal plexus (CN10)
- Styloglossus muscles
- most lateral tongue muscle
Origin:
- from **styloid process (temporal bone) to **side of tongue
Nerve supply:
- CN12
Movement of tongue
Function:
- sucking, prehension of food, chewing, swallowing, speaking, toileting, gestures
- **Shape —> altered by Intrinsic muscles:
- transverse: narrow tongue and heaps up dorsum into convexity
- transverse + vertical: dorsum convexity flattened —> smaller cross-sectional area —> elongate
- transverse + vertical + genioglossus (lowest fibres) —> protrude tongue
- **Position —> altered by Extrinsic muscles:
- Genioglossus: ***Protrude root of tongue (lower fibres)
- Styloglossus: ***Retract + Elevate tongue
- Hyoglossus: Draw the side ***downwards
- Palatoglossus: ***Elevate tongue
Mylohyoid: elevate floor of mouth —> elevate tongue
Tongue and Uvula lesion
Right CN12 lesion
—> Right genioglossus affected
—> Unopposed left side protrusion
—> Tongue protrude to right side
Right CN10 lesion
—> Right Muscular uvulae affected
—> Unopposed left side contraction
—> Uvula deviate to left side
Frenulum of tongue (脷根)
Mucous membrane fold extending from floor of mouth
—> midline of inferior tongue
Either side:
Opening of Submandibular and Sublingual gland
Tongue and swallowing
Food is masticated —> forming bolus —> conscious decision to swallow —> tongue push bolus backwards into oropharynx —> trigger swallowing reflex
- Soft palate raised (Levator veli palatini) —> temporarily close off nasopharynx from oropharynx
- Pharyngeal muscles constrict in sequence —> pushing bolus into esophagus
- Larynx elevates —> epiglottis close off larynx
- Esophageal muscles drive bolus down by peristalsis
Blood supply of tongue
Artery:
- Lingual artery
- branch from anterior branch of ***External carotid artery
- passes deep to Hyoglossus towards tongue tip
Venous drainage:
- Deep lingual veins (Ranine veins): undersurface of tongue —> Common facial vein —> Internal jugular vein
- Lingual veins —> Internal jugular vein
Sensory innervation of tongue
Anterior 2/3
- general sensory: Lingual nerve (CNV3)
- special sensory: Chorda tympani (CN7) (via Lingual nerve)
- secretomotor (parasympathetic): Chorda tympani (CN7) (via Lingual nerve)
Posterior 1/3
- general sensory, special sensory, secretomotor (parasympathetic): CN9
Floor of mouth
- Mylohyoid muscle (最底層)
- Geniohyoid muscle
- Hyoid bone
- Mylohyoid muscle
Origin:
- ***Mylohyoid line (Mandible)
Insertion:
- Midline raphe
- ***Hyoid bone (posterior fibres)
Nerve supply:
- ***CNV3
- Geniohyoid muscle
- Above Mylohyoid
- Below Genioglossus
- Important for positioning of hyoid bone —> positioning of larynx
Origin:
- ***Inferior genial tubercle (Mandible) (Genioglossus: Superior genial tubercle)
Insertion:
- upper border of ***Hyoid bone
Nerve supply:
- ***C1 (via CN12) (即係由C1黎 —> hitchhike CN12)
***3. Hyoid bone
- U shape
- Above larynx
- Slung between Mandible and Styloid process by Geniohyoid (前) and Stylohyoid (後)
- Important in positioning of larynx
- **Elevate hyoid:
1. Geniohyoid (C1 via CN12)
2. Stylohyoid (CN7)
3. Mylohyoid (CNV3) - **Depress hyoid (Infrahyoid muscles):
1. Thyrohyoid (Ansa cervicalis)
2. Omohyoid (Ansa cervicalis)
3. Sternohyoid (Ansa cervicalis)
(4. Sternothyroid —> drag entire larynx down) (Ansa cervicalis)
***Hyoglossus as landmark
Lateral (Superficial) to Hyoglossus:
- Lingual nerve (Submandibular ganglion for preganglionic cell from Chorda tympani CN7)
- CN12
- Submandibular duct
- Stylohyoid muscle
Medial to Hyoglossus:
- CN9
- Lingual artery
- Genioglossus
- Stylohyoid ligament
Submandibular gland
Superficial part
- below / lateral to Mylohyoid
- lies in Submandibular fossa
- covered by deep cervical fascia
- curves around posterior border of Mylohyoid (包住Mylohyoid的後面)
Deep part
- above / medial Mylohyoid
- lies in floor of mouth
- between mandible and side of tongue
- **Submandibular duct
- opening at anterior end of deep part —> ***Sublingual papilla
- runs between Sublingual gland and Genioglossus
Anatomical relationships:
- Facial artery: grooves the gland (before turning around inferior border of mandible)
- Common facial vein: grooves the gland
- CN7 Mandibular branch: crosses the gland
Sublingual gland
- in front of Anterior border of Hyoglossus
- between Mylohyoid and Genioglossus
- below termination of Submandibular duct
- about 15 ducts
—> 1/2 open into Submandibular duct —> Sublingual papilla
—> 1/2 open directly on Sublingual fold + Sublingual papilla
Teeth
Deciduous teeth (milk teeth) —> total 20
- central and lateral incisors
- canine
- 2 molars
Permanent teeth —> total 32
- central and lateral incisors
- canine
- 2 premolars
- 3 molars
Upper: Maxillary teeth
Lower: Mandibular teeth
Teeth nerve supply
Upper: CNV2 (Superior alveolar nerve: anterior, middle, posterior)
Lower: CNV3 (Inferior alveolar nerve)
Dental occlusion
Class I: Normal
Class II: Distal occlusion: Maxilla protrude anteriorly
Class III: Mesial occlusion (倒及): Mandible protrude anteriorly
