1. GI tract Oral Cavity .pptx Flashcards
Describe the bones and structures that form the boundaries of the oral cavity
Anteriorly: The cavity extends from the upper and lower lips
Posteriorly: To the palate-glossal arches
Laterally: To the cheeks
The cavity “proper” is between the teeth, the vestibule is outside the teeth
Bones: Hard palate (made up of maxilla and horizontal plate of palatine), Teeth, Mandible
Describe the orientation of the B, R, A of the mandible
The Body and Ramus is divided by the Angle.
The Ramus then divides into condylar and coronoid processes
What is the importance of the Retromolar fossa on the medial aspect of the mandible?
Retromolar fossa for attachment of the lower end of the pterygomandibular raphe, between buccinator and superior constrictor
What is the importance of the mandibular foramen on the medial aspect of the mandible?
Mandibular foramen for the inferior alveolar or dental nerve to the lower teeth
What is the importance of the submandibular fossa on the medial aspect of the mandible?
Submandibular fossa for the submandibular gland
What is the importance of the mylohyoid line on the medial aspect of the mandible?
Mylohyoid line, for the attachment of mylohyoid muscle, forming the
floor of the mouth
What is the importance of the sublingual fossa on the medial aspect of the mandible?
Sublingual fossa for the sublingual gland
What is the importance of the sublingual fossa on the medial aspect of the mandible?
Sublingual fossa for the sublingual gland
What actions at the temporomandibular joint allow opening and closing of the mouth?
Closing: Retraction and elevation
Opening: Protrusion and depression
Opening of the mouth:
What is the primary muscle of the action and how?
Which joint cavity does the movement occur in?
What contributes the movement and how?
Primary muscle of opening: Lateral pterygoid muscle by drawing the draw + condyle forwards and downwards
Cavity: Movement in upper cavity
Gravity and digastric muscle contribute by rotation occurring the in lower joint cavity
Closing of the mouth (elevation):
Main muscles?
Main muscles: Medial pterygoid, masseter and temporalis
Facial muscles:
Name 4 main muscles?
Name their general attachment?
Main muscles: Buccinator, depressor anguli oris, orbicularis oris, lavator anguli oris
What is the structural similarity of the lips and cheeks?
The lips and cheeks are a “sandwich” of muscles of facial expression, with skin externally and non-keratinised, stratified squamous epithelium lining the mucous membrane internally
Buccinator:
Relation between fibres and lips
Modiolus?
How does it allow continuity between the oral cavity and the pharynx?
The upper fibres contribute to the upper lip and cross over to into the lower lip. Vice versa for the lower fibres
Modiolus= The point of cross over between the upper and lower buccinator fibres
Buccinator attaches to the maxilla and mandible but also fuses with the superior pharyngeal constrictor at the pterygo-mandibular raphe
What is the upper and lower attachments for the pterygo-mandibular raphe?
Lower: Over the retromolar fossa
Upper: Pterygoid hamulus (at the lower end of the medial pterygoid plate)
Sensation to the skin of the cheeks and lips, and the corresponding, internal mucous membrane is by branches from ???
By branches from the Maxillary and Mandibular divisions of the Trigeminal Nerve (Cranial V), V2 and V3
What is the main muscle of the floor of the mouth?
Muscular diaphragm of mainly mylohyoid (left and right)
Tongue muscles: Made up of which main muscles? Nervous supply? Muscular interplay? Actions of extrinsic muscles?
Within tongue: Genioglossus plus intrinsics
Attach to bone: Extrinsics i.e. palatoglossus; hyoglossus; styloglossus
Tongue muscles are supplied by the Hypoglossal nerve (Cranial XII), except palatoglossus which is supplied by vagus (CN X)
Muscular interplay: extrinsics alter position; intrinsics alter shape.
Upwards and backwards: Palatoglossus (from the palatine aponeurosis) and
Styloglossus (from the styloid process)
Draws the sides down: Hygoglossus
What structure divides the tongue?
The terminal sulcus divides it into an anterior 2/3 and a posterior 1/3, or pharyngeal part
Nervous supply of tongue sensation?
Ant 2/3 is via lingual (V3) for general sensation and taste
Post 1/3 glossopharyngeal (Cranial IX) for both general sensation and taste
Arterial and venous supply of the tongue?
Lingual artery (from external carotid) Deep and dorsal venous systems, then converging on the internal jugular
Tongue lymph drainage
- -> Inferior deep cervical lymph nodes
- -> Submandibular lymph nodes
- -> Submental lymph nodes
- -> Superior deep cervical lymph nodes
CROSSES MIDLINE
Mainly to deep cervical nodes to then drain into the internal jugular vein
What are the 3 salivary glands?
What is their function?
What is their nervous supply?
Parotid, submandibular and sublingual
Function: Commence digestion, lubricate food, maintain teeth/gum health
Nervous supply: Receive a parasympathetic, secretomotor supply from the Glossopharyngeal nerve (IX) and Facial nerve (VII)
Where and how does the sublingual gland drain?
Via separate ducts into the floor of the mouth
Where and how does the submandibular gland drain?
Submandibular ducts which are beside the sublingual glands but open at the papillae, either side of the frenulum
What 3 structures are contained within the parotid gland?
- Facial nerve
- Retro-mandibular vein
- External carotid artery
Two muscles of the palate?
Tensor palati
Levator palati
What makes up the Pillars of the Fauces?
Palatoglossal and Palatopharyngeal Arches with Palatine Tonsil between
Tensor palati
Attaches to the fossa above the medial pterygoid plate and to the cartilage of the auditory tube
Lies outside the med. pter. plate and outside the pharynx, until it becomes tendinous, curves around the pterygoid hamulus and flares into the soft palate as the palatine aponeurosis that attaches to the hard palate, but is free posteriorly
Levator palati
Arises from the apex of the petrous temporal bone and from the cartilage of the auditory tube
Lies inside the pharynx and inserts into the upper aspect of the palatine aponeurosis
Nervous and arterial supply of palates?
The greater and lesser palatine branches of the maxillary nerve and artery supply the hard and soft palates respectively, with an addition from the nasopalatine anteriorly
The glossopharyngeal nerve (IX) supplies the ___ and may encroach on to the soft palate – referred pain to middle ear
The glossopharyngeal nerve (IX) supplies the TONSILS and may encroach on to the soft palate – referred pain to middle ear
The Uvula receives the ___ ___ and hangs off the soft palate, contributing to its functions
The Uvula receives the MUSCULUS UVULAE and hangs off the soft palate, contributing to its functions
Changes that occur in the oral cavity during chewing and swallowing?
While chewing food, the oropharyngeal isthmus must be closed –
palatoglossus and palatopharyngeus contract to draw the palate down and the tongue slightly upwards, (i.e. towards each other), as well as drawing the palatoglossal and palatopharyngeal arches downwards and medially – like curtains
When swallowing, tensor palati makes the aponeurosis tense so that levator palati can lift it to close the nasopharyngeal isthmus
Teeth:
4 quarters of teeth?
Total?
Nervous supply?
Each quarter: Molars – 3 Premolars – 2 Canine – 1 Incisors – 2
Total – 8
X4 = 32
The upper teeth are supplied by the alveolar (dental) branches of the maxillary nerve (V2) that also supply the maxillary sinus. The lower teeth are supplied by the inferior alveolar (dental) branch of V3
