Oral cavity Flashcards
What are the boundaries of the oral cavity?
- Roof: Palate
- Floor: Mandible and mylohyoid
- Lateral walls (3 layers):
1. Skin
2. Muscle (buccinator)
3. Oral mucosa - Posterior:
1. Palatoglossus
2. Palatophayngeus
What is significant about the 2 muscles of the posterior oral cavity?
- Palatoglossus (anterior) and palatopharyngeus (posterior) make up the palatoglossal and palatopharyngeal arches.
- Bilateral arches make up the anterior and posterior tonsillar pillars.
- Between the arches is the tonsillar fossae in which lie the palatine tonsils.
What are the components of the palate?
- Bony hard palate (anterior)
- Muscular soft palate (posterior)
What are the muscles of the soft palate?
- Tensor veli palatini
- Levator veli palatini
- Palatopharyngeus
- Palatoglossus
- Musculus uvulae
What are the bones of the hard palate?
- Palatine process of maxilla
- Horizontal plate of palatine bone
What is the structure of the tongue?
- The tongue is divided into 2 parts, anterior 2/3 (oral part) and posterior 1/3 (pharyngeal part), by sulcus terminalis.
- The oral part is covered by filiform (most common) or fungiform papillae.
- Anterior to the sulcus terminlais is a row of circumvallate papillae.
- Pharyngeal is nodular as a result of the underlying lingual tonsils.
What are the muscles of the tongue?
- Intrinsic (changes shape of tongue):
1. Longitudinal (superior/inferior)
2. Transverse
3. Vertical - Extrinsic (moves position of tongue):
1. Genioglossus
2. Hyoglossus
3. Styloglossus
4. Palatoglossus
What is the nerve supply to the muscles of the tongue?
All muscles of the tongue are supplied by the hypoglossal nerve [XII] except palatoglossus which is supplied by the vagus nerve [X] via the pharyngeal plexus.
What is the sensory supply to the tongue?
- Somatic sensation to the anterior 2/3 of the tongue is supplied by the lingual nerve (branch of mandibular division of trigeminal) while taste is supplied by the chorda tympani (facial nerve [VII]).
- Somatic sensation and taste to the posterior 1/3 of the tongue is supplied by the glossopharyngeal nerve [IX].
- Small part of tongue above epiglottis is supplied by the internal laryngeal branch of the vagus nerve [X].
What are the salivary glands?
What is the structue of the temporomandibular joint (TMJ)?
- Articulation between the head of the mandible and the articular tuberce/mandibular fossa of the temporal bone.
- Atypical synovial joint divided into superior and inferior parts by fibrocartilage articular disc.
What are the functions of the 2 parts of the joint?
- Upper part: Allows gliding of the head of mandible out of mandibular fossa onto articular tubercle during protrusion/retraction.
- Lower part: Allows hinge-like movement of the mandible in the mandibular fossa during elevation/depression.
What are the ligaments associated with the TMJ?
- Temporomandibular (lateral) ligament: Runs from margin of articular tubercle to neck of mandible.
- Sphenomandibular ligament: Runs from the spine of the sphenoid to the medial side of the mandibular ramus.
- Stylomandibular ligament: Runs from styloid process to angle of the mandible.
What are the movements associated with the mandible?
- Elevation:
Masseter
Temporalis
Medial pterygoid
- Depression:
Protrusion: Lateral pterygoids
Depression: Gravity, digastric, infrahyoids
- Protrusion: Medial/lateral pterygoids
- Retraction: Temporalis
-
Grinding (alternate protrusion/retraction of each side):
1. Medial/lateral pterygoids
2. Temporalis
What are the muscles of mastication?
- Masseter
- Temporalis
- Medial pterygoids
- Lateral pterygoids
