Session 4: Anatomy of biting, chewing and swallowing [Complete] Flashcards
An alternative name for the mouth is?
Buccal cavity
What are the 2 main folds in the mouth
Palatopharyngeal fold (palate [roof of the mouth] to pharynx)
Palatoglossal fold (palate to tongue)
Where is the palantine tounsil located?
Between the palatopharyngeal and palatoglossal fols
The posterior wall of the oral cavity is known as?
Oropharynx
What is the uvula?
A part of the soft palate
Why do doctors ask you to say ‘ahh’
Tests the vagus nerve (which provides most motor innervation to the levator veli palatini muscles)
The levator veli palatini muscles should cause the soft palate and uvula to lift up.
What occurs if there is a problem with vagus nerve on one side of the soft palate
Levator velli palatini muscle won’t elevate, but the levator palatini muscle on the other side (where vagus is functioning) will elevate normal, so uvula will deviate towards the functioning side (which goes up!), so uvula will deviate AWAY from the lesion.
(OPPOSITE with tongue)
What are the 3 components of the pharynx?
Nasopharynx
Oropharynx
Laryngopharynx
N.B. posterior to the airway is the opening of the oseophagus
What is the name of the border between the nasopharynx and the oropharynx?
Pharyngeal isthmus /nasopharyngeal isthmus
What structure is present at the border of the oropharynx and laryngopharynx?
The epiglottis
How is food stopped from going down the airway?
You will raise the layrnx, you retroflex the epiglottis and cover the airway
Describe the location of the hard and soft palate and describe their form
Hard palate is located anterioriorly and formed by the palatine process of the maxilla and horizontal plate of palatine bone, and spans the arch formed by the upper teeth
The soft palate is located posteriorly with the uvula in the midline
Area where food can get stuck inc. fishbones
Piriform fossa which are located on either side of the laryngeal orifice
Name the muscles of the pharynx and state their function.
Describe their sensory and motor innervations.
Constrictor muscle: pushes bolus into GI tract by sequential contraction.
There are superior, middle and inferior constrictor muscles
Sensory: IX (glossopharyngeal) and X (vagus) innervation via pharyngeal plexus
Motor: X (vagus) and (XI) [Accesory], constriction
Outline stages of swallowing
The tounge is lifted and retracted via styloglossus and intrinsic muscles, causing the bolus to enter the oropharynx with the aid of the palatoglossus.
The bolus is prevented from entering the nasopharynx by raising the soft palate and closing it off. It is also prevented from entering the airway by raising the larynx and retroflex of the epiglottis.
Peristaltic waves of contraction from the constrictor muscles aid the bolus into the oesophagus and the cricopharyngeal muscle relaxes to provide an opening into the oesophagus
State the names of the 3 pairs of salivary glands
Parotid (largest)
Sublingual
Submandibular
What type of liquid comes from each salivary gland
Parotid and submandibular mainly serous
Sublingual maily mucus
Which cranial nerves are each salivary gland supplied by
Parotid- IX (Glossopharyngeal)
Submandibular and sublingual- VII (Facial)
N.B. The facial nerve emerges from the parotid gland however it does not innervate it
Where does the fluid drain into mouth from the parotid gland?
Via parotid duct, which opens above the upper second molar
Which muscle does the parotid canal penetrate to get to thesecond molar?
Buccinator muscle
N.B Label incorrect it is the muscle you see the duct coming out of.
List the muscles of the tongue and their points of attachment
Styloglossus - to styloid process of temproal bone= help to tounge to retract
Hyoglossus (to hyoid)
Genioglossus (to mandible)
intrinsic muscles
Which cranial nerve supplies motor innervation to muscles of the tongue
XII [Hypoglossal]
Apart from palatoglossus which is innervated from vagus CNX.
What is the attachment and function of the genioglossus?
Its function is to protrude the tongue
Genioglossus emerges from mandible (anteriorly) and inserts onto the tongue and hyoid bone
It protrudes the tongue when this muscle contracts (kind of pulls it forward towards mandible when this muscle shortens)
How is the genioglossus function tested? What would happen to function if nerve supply was damaged on one side?
Ask them to stick tongue out.
If there is no innervation, the tongue is pulled forward on one side and not the other, and it pulls TOWARDS the lesion
What is the lingual nerve function? What cranial nerves is it derived from?
Sensation as well as taste perception.
Derived from mixed cranial nerve
What is the name of the ganglion under the tongue? What type of innervation does it supply?
Submandibular ganglion.
Provides vagus innervation to salivary glands
Compare the sensation vs taste innervation of the tongue
Anterior 2/3. Taste= facial nerve (VII) Sensory= trigeminal (V)
Posterior 1/3. Taste and sensation= glossopharyngeal (IX) and SOME vagus
Where does taste perception begin?
nucleus solitarius in medulla
List superficial muscles of mastication, their function and their innervation.
Masseter: zygomatic arch of zygomatic bone to the lateral surface of the ramus of the mandible
It elevates the mandible, allowing forced closure of the mouth.
Temporalis- THIN temporal fossa to coronoid process of mandible elevates and retracts mandible
All mastication from trigeminal
List the deep muscles of mastication and innervation
Lateral pterygoid: lateral pterygoid plate [of sphenoid] to the neck of mandible
It depresses and protracts mandible to open mouth
Medial pterygoid: lateral pterygoid plate of sphenoid/ maxilla/palate to angle of mandible
It elevates and protracts and lateral movement of mandible for chewing
Innervated by Trigeminal (vs buccinator is cn7)
Where does the mandible articulate in the temporomandibular joint
It articulates into the mandibular fossa of the temporal bone
What kind of joint is the temporomandibular joint?
Joint capsule
Composed of two synovial cavities separated by articular disc
What component of the temperomandibular joint is located most anteriorly?
the articular tubercle of the temporal bone anteriorly
State the movement in the temporomandibular joint when opening the jaw slightly vs widely
Slightly- hinge action between the head of the mandible and the mandibular fossa of the temporal bone
Widely opened- both hinge movement within the mandibular fossa, but the head of the mandible also GLIDES anteriorly to the articular tubercle of the temporal bone
Reason of articular disc = allow protrusion/retraction as well as elevation/depression
What can occur in anteriotly dislocated jaw dyslocation
Jaw opens so widely that it glides across the articular tubercle of temporal bone into the infratemporal fossa (where there are vessels and nerves)
How can you put the mandible back in place?
Must put thumbs on back molars, push down (to get pass the articular tubercle) and then back into the mandibilar fossa
At what level does the common carotid bifurcate?
Laryngeal prominence
List the branches of the external cartotid artery
Superior thyroid
Ascending pharyngeal
Lingual
Facial
Occipital
Posterior auricular
Maxillary
Superficial temporal
What does the superior thyroid branch of the external carotid artery penetrate?
thyroid cartilage
Why is the ascending pharyngeal artery hard to see?
It originates posteriorly
Describe the route of the facial artey
Around the inferior border of the mandible up to medial canthas of the eye.
It has a loop that allows movement as it goes around the mandible which is always opening and closing
Which important artery emerges from the maxillary artery?
The middle meningeal artery—-> this branch comes through formaen spinosum
Describe the course of the facial nerve.
It emerges from the pontomedullary junction,and then passes through the internal auditory meatus with the vestibulocochlear nerve (CN 8)
It passes through the temporal bone and emerges from the stylomastoid foramen.
It passes underneath the parotid and then the 5 branches of the facial nerve emerge from the anterior border of the parotid gland….. PAROTID GLAND IT NOT INNERVATED BY THE FACIAL NERVE
List the 5 branches of the facial nerve emerging from the parotid.
Temporal
zygomatic
buccal
mandibular
cervical (supplying the platysma)
N.B. You can test facial nerve by asking them to look up and should have creases in forehead
Describe the course and then two branches of the mandibular nerve.
Mandibular nerve passes through the foramen ovale and then splits into:
1.Inferior alveolar nerve which passes into the back of the mandible and it travels through the mandible.
It provides sensory nerves for lower dentition. (lower teeth)
- The lingual nerve supplies sensory innervation to anterior 2/3 so contains V3 fibres.
But it also has facial nerve branches from the chorda tympani (branch of the facial nerve emerging in the temporal bone).
Information flow in chorda timpani is bidiretional as they are parasympathetic to submandibular ganglion (to submandibular and sublingual salivary gland) AND provide taste fibres from the anterior 2/3 of the tongue.
What is the terminal branch of the inferior alveolar nerve?
The mental nerve (relating to mens=chin)
How do you test V3 (mandibular branch) function of the trigeminal nerve?
should experience sensation to the chin
Describe the dermatomes of head and neck
V1 (Opthalmic branch)= forehead + eyeball (corneal reflex)
V2 (Maxillary branch) = below eyes + nose + cheeks + upper teeth
V3 (Mandibular branch) = lower teeth + tongue + chin + thin strip of skin on lateral side of face going up to temples (think of sideburns)
Posterior of head is C2-C3
Neck is C4-C5
Describe the innervation of the buccal cavity
Hard palate: Greater palatine, nasopalatine nerves (both V2)
Soft palate: lesser palatine nerve (V2)
Floor of oral cavity: lingual nerve (V3)
Cheeks: Buccal nerve (=V3, distinct from buccal branch of facial nerve.)
What is the name and function of the recess at the back of the tongue?
Epiglottice vallecula (recess which allows saliva to collect until next swallow so the saliva doesn’t constalty evoke a swallow reflex)
