Oral Cavity Flashcards
Oral Cavity Borders
- Hard & Soft Palate = roof
- Tongue & sublingual region = floor
- Teeth & gums = anterior/lateral walls
- Palatoglossal arches = posterior/lateral walls
Palate: Hard vs. Soft
- Hard Palate = anterior 2/3 – Maxilla & Palatine bone
* Soft Palate = posterior 1/3 – Muscle tissue & uvula
Soft Palate
• Palatine glands – mucous glands add thickness anteriorly • Aponeurosis – adds strength to anterior 1/3 • Muscles – add mobility to posterior 2/3
Tensor Veli Palatini m.
Found in soft palate • Arises from sphenoid bone • Descends & turns 90° around medial pterygoid hamulus • Insert into palatine aponeurosis • Tenses & depresses soft palate
Levator Veli Palatini m.
Found in soft palate
• Arises from temporal bone & auditory tube
• Inserts into palatine aponeurosis
• Located just posteriomedial to tensor veli
palatini m.
• Elevates & retracts soft palate
Soft Palate: Vascular Supply
• Descending palatine a.
– Gives rise to greater & lesser palatine aa. – Descends thru palatine canal
– Greater Palatine a.
• Suppliesanteriorpalate
• Passesthrugreaterpalatineforamen
– Lesser Palatine a.
• Suppliesposteriorpalate
• Passesthrugreaterorlesserpalatineforamen
• Venous drainage via Pterygoid & Pharyngeal plexuses
Soft Palate: Sensory N. Supply
Nasopalatine n. (CN V2) – Supplies tip of palate – passes thru incisive canal Greater Palatine n. (CNV2) – Supplies anterior palate – Passes thru greater palatine foramen Lesser Palatine n. (CN V2) – Supplies posterior palate – Passes thru lesser palatine foramen Travel with greater & lesser palatine vessels
Soft Palate: Motor N. Supply
• Mandibular n. (CN V3) – Supplies tensor veli palatini m. • Vagus n. (CN X) – Supplies levator veli palatini m. – All other mm. of palate (4) supplied by Vagus n. (via pharyngeal plexus)
Palatine Tonsils
• Bilaterally in oropharynx in tonsillar bed (fossa)
– Between palatoglossal arch & palatopharyngela arch
– Located between soft palate & lingual tonsil
• Note: with age, tonsils may become inconspicuous
Palatine tonsils: Arterial Supply
• Tonsillar brs of lingual & facial aa. – Both brs. of external carotid a. • Ascending pharyngeal a. – Br. of external carotid a. • Lesser palatine a. – Br. of descending palatine a.
Clinical Notes: Tonsillectomy
• Palatine tonsils may be removed
• Heavy bleeding may occur from aa.
• Bleeding from paratonsillar v. also common – Venous drainage from tonsillar bed region
• CN IX lies on lateral pharyngeal wall
– Vulnerable to injury because lateral wall is thin
Features of Oral Cavity
- Sublingual region - under tongue
- Lingual frenulum – attaches tongue to floor of mouth
- Opening of submandibular duct – on each side of frenulum
- Sublingual fold – mucosal fold overlying sublingual gland
Sublingual Gland
• Found inferior to sublingual fold & superior to mylohyoid m.
– Remember: mylohyoid is foundation for oral cavity
• Numerous ducts from gland open onto surface of fold
– Some may unite with submandibular duct
Submandibular Duct
- Wharton’s duct
- Originates in submandibular gland
- Runs along medial aspect of sublingual gland
- Ends anteriorly & lateral to the frenulum of tongue (bilaterally)
- Crossed TWICE by the lingual n.
Lingual N.
- Br. CN V3
- Emerges between lat. & med. pterygoid mm.
- Passes post. To 3rd molar
- Spirals around submandibular duct lateral to hyoglossus m.
- Crosses from supr./lat. to infr. to supr./med.
- Ends with several brs piercing ant. 2/3 tongue
Submandibular Ganglion
• ~Level of 3rd molar
• Suspended from lingual n.
by 2 or more short n. brs.
• Relays p-symp. Fibers from chorda tympani (CNVII)
• These fibers travel to submandibular and sublingual glands
• Symp. Fibers to glands are from external carotid plexus
Hypoglossal N. (CN XII)
- Deep to post. belly digastric and stylohyoid mm.
- Runs anterior between submandibular gland and hyoglossus m.
- Inferior to lingual n.
- Superior to mylohyoid m.
- Ends in posterior tongue to provide motor innervation
Glossopharyngeal N. (CN IX)
- Runs lateral to stylopharyngeus m. to enter pharynx
- Between superior & middle constrictor mm.
- Continues anteriorly thru tonsillar region
- Ends in posterior tongue to provide sensory innervation
Muscles of Tongue
• Styloglossus m. – Styloid process to tongue • Hyoglossus m. – Hyoid bone to tongue • Genioglossus m. – Genoid tubercle of mandible to tongue • Intrinsic mm. – Vertical, transverse & long fibers
Clinical Notes: Genioglossus m.
•Paired mm. fused in midline that serves to protrude tongue
• Unilateral paralysis of CNXII affects straight protrusion – Intact side protrudes more than affected side
– Results in deviation of tongue toward paralyzed side
• Bilateral paralysis results in inability to protrude tongue – Tongue falls back & may occlude airway (suffocation)
Oral Cavity: Arterial Supply
• Facial a. – supplies most of superficial structures
• Lingual a. – supplies most of deeper structures – 3 brs. to tongue region
– Dorsal Lingual a., Deep lingual a., & Sublingual a.
• Accompanying vv. provide venous drainage to IJV – Tongue falls back & may occlude airway (suffocation)
Tongue: Special Sensory
• Chorda tympani n. (CNVII) – Taste to anterior 2/3 – Fibers travel with lingual n. • Glossopharyngeal n. (CN IX) – Taste to posterior 1/3 tongue
Tongue: General Sensory
• Lingual n. (CNV3)
– Sensory to anterior 2/3 tongue
• Glossopharyngeal n. (CN IX)
– Sensory to posterior 1/3 tongue
Innvervation to Maxilla
• Ant. Supr. Alveolar n.– br. of Infraorbital n.(CNV2) – supplies incisors & canines
• Mid. Supr. Alveolar n.– br. of Infraorbital n.(CNV2) – supplies premolars & mesiobuccal root of 1st molar
• Post. Supr. Alveolar n.–br. of Maxillary n.(CNV2) – supplies molars, except mesiobuccal root of 1st molar
** Plexuses & variations exist
Innervation to Mandible
• Inferior Alveolar n.
– Br. of CN V3
– Supplies all mandibular teeth
Oral Cavity: Arterial Supply
- Approx. corresponds to nerve supply of teeth
- Ant. Supr. Alveolar a. – br. of Infraorbital a.
- Mid. Supr. Alveolar a. – br. of Infraorbital a.
- Post. Supr. Alveolar a. – br. of Maxillary a.
- Inferior Alveolar a. – br. of Maxillary a.
