Unit 10: Chewing Flashcards
What joint is responsible for chewing?
The TMJ
The temporomandibular joint
What are the two different direction of travel of the mandible?
The inferior angle
The anterior angle
Change between these two directions is known as the angle of the mandible
What is the purpose of the mental foramen?
Bilater structure in the anterolateral surface of the mandible.
For passage of the mental nerve, which is a branch of CNV3
What are the alveolar processes on the mandible?
Bony indentations or grooves, mark areas that act as sockets for the teeth.
What type of joint is the TMJ?
Modified synovial hinge joint
Why is the TMJ classified as a modified hinge joint?
Allows movement in three planes (elevation/depression, protraction/retrotraction, lateral)
Hinge joints normally only allow movement in two planes
What makes up the TMJ joint?
Mandibular fossa on the temporal bone.
Condyle of mandible.
An the articular tubercule on the temporal bone
What is the anterior boundary of the oral cavity?
Lips and associated musculature including the obicularis oris
What is the function of the obicularis oris?
Purse of lips e.g around a straw
What are the different sections of the oral cavity?
Oral fissure
Oral vestibule
Oral cavity Proper
What are the boundaries of the oral fissure?
Is the space between the lips (where food/air passes in/out)
What are the boundaries of the oral vestibule?
Is the space between the teeth and the lips
What are the boundaries of the oral cavity proper?
Area where tongue and food mainly sit
Within the dental arches (teeth)
What is the superior boundary of the oral cavity?
The hard palate (anteriorly) and the soft palate (posteriorly.
What makes up the hard palate?
The palatine bone and the palatine process of the maxilla, also may have contributions from the alveolar process of the maxilla
What makes up the soft palate?
Uvula and soft muscular tissue
What is the function of the soft palate when swallowing?
Is mobile
Moves to block off the nasal cavity
Prevents bolus from passing into the nasal cavity
What is the inferior boundary of the oral cavity?
Mainly soft tissue
Include suprahyoid muscles
What is the function of the tongue?
Speech
Oral hygeine
Swallowing
Taste
What is the lateral border of the oral cavity?
Soft tissue
Mainly made up of the buccinator muscle
Draw a diagram to represent the different sections of the tongue?
The apex
The body
The terminal groove
The root
How does the terminal groove divide the tongue into sections?
Seperates the body and the root
Also marks as a landmark between the anterior 2/3 and the posterior 3 of the tongue.
What is the innervation to the anterior 2/3 tongue?
Taste - by CN7 facial
General sensation - by CNV3 (temp, texture) (mandibular branch of trigeminal nerve)
What is the innervation to the posterior 1/2 of the tongue?
Taste and general sensation by CN9. Glossopharangeal
What provides the motor innervation to the tongue?
CN12 hypoglossal
Provides to the intrinsic and extrinsic muscles.
What type of innervation activates the salivary glands?
Parasympathetic nervous system
What are the different functions of saliva?
Oral hygeine
Moist mucosa
Lubricate for the passage of bolus
Digest starch
Protect teeth
List the three different salivary glands from largest to smallest
Parotid
Submandibular
Sublingual
What nerve provides inervation to the parotid salivary gland?
CN9
What nerve provides innervation to the sublingual salivary gland?
CN7 facial
What nerve provides innervation to the submandibular salivary gland?
CN7 facial
Describe the structure of the parotid salivary gland.
Has a deep and superfifical component, seperated by wrapping around the masseter muscle and the mandible
What is the passage of the duct from the parotid gland?
Travels anterior to the masseter then pierces the buccinator
Is identified in the oral cavity at roughly the level of the second molar
What is the general passage of the duct from the sublingual gland?
Has many ducts
Pierce the inferior floor
Pass through the submucosa to release under the tongue
What is the general structure of the submandibular salivary gland?
Has a superficial and deep component
Wraps around the mylohyoid muscle
What is the passage of the duct from the submandibular salivary gland?
Duct develops from the deep portion of the gland
passes through soft tissue in the floor
Opens medially near the frenulum of the tongue into the oral cavity.
What is the posh word for chewing?
Mastication
What are the main muscles of mastication?
The temporalis
The masseter
The medial pterygoid
The lateral pterygoid
What is the general point of attachement of the temporalis muscle?
Originates from temproral fossa and inserts onto coronoid process
What is the general point of attachment of the masseter muscle?
Originates from the zygomatic arch to the angle of mandible
Note has a deep and superficial head
What is the general point of attachment of the medial pterygoid muscle?
Superficial head: maxillary tuberosity
Deep head: medial surface of lateral pterygoid plate
Inserts onto the internal surface angle of mandible
What is the general point of attachement of the lateral pterygoid muscle?
Both insert onto the neck of the mandible/ articular disk of TMJ
Upper head - inserts into infratemporal fossa
Lower head - inserts into lateral surface of the lateral ptreygoid
What muscles are mainly respnsible for closing the jaw?
Temporalis
Masseter
Medial pterygoid
What muscles are mainly responsible for opening the jaw?
Lateral Pterygoid muscles
What muscles may aid the lateral pterygoid in opening the jaw?
The platysma
The anterior belly of the digastric muscle
How is the TMJ joint divided and what is the functional significance of this?
Articular plate divides into an upper and lower section
Upper section is protraction and retraction
Lower section is elevation and depression
In order for the jaw to open (be depressed) what way must it move first?
Anteriorly
What structure prevents anterior dislocation of the jaw?
The articular tubercule on the zygomatic arch
What happens if the jaw is dislocated anteriorly?
Condyle of the mandible passess anteriorly to the articular tubercle
Causes spasm of the muscle of mastication
Struggle to open the jaw and struggle to position backwards
How do you fix and anteriorly dislocated jaw?
Put downwards pressure on the inferior molar to overcome spasm of the muscles of masstication
Then guide condyle backwards into the mandibular fosso on the temporal bone.
What structures support the TMJ synovial joint?
The joint capsule
The temporomandibular ligament
The sphenomandibular ligament
The stylomandibular ligament
What is the function of the temporalmandibularligament?
Prevents posterior dislcoation of the jaw
What is the function of the sphenomandibular ligament?
Prevents lateral dislocation of the jaw? (breaks when force is applied from the lateral side)
What is the function of the stylomandibular ligament?
Prevents lateral dislocation of the jaw (breaks when pressure on the medial side)
What does bilateral movement of the lateral pterygoid muscle result in?
Protrude jaw (allos to open)
What does unilateral movement of the lateral/medial pterygoid muscles result in?
Movement of the jaw to the contralateral side?
What does bilateral movement of the medial pterygoid result in?
Protraction and elevation of the jaw
What are the different fibres directions in the temporalis and how does this affect its function?
Vertically orientated fibres - elevate the mandible
Posterior/horizontal fibres - retract the mandible.
Describe the position of the different salivary glands
What is the blue label?
Coronoid process
What is the yellow label?
Mandibular notch
What is the green label?
Condyloid process
What is the pink label?
The neck
What is another term for the head of the mandible?
The Condyloid process
What is the red label?
The ramus
What is the orange label?
The angle
What is the green label?
The mandibular foramen
What is the function of the mandibular foramen?
Contains neurovasculature to the teeth
Wha it’s the pink label.
Submandibular fossa
What is the function of the submandibular fossa?
Contains the submandibular salivary gland
What features can you identify that surround the TMJ? Green
The mastoid process
The styloid process
The external acoustic meatus
Can you identify the bones around the TMJ joint? Blue
Temporal
Sphenoid
Zygomatic
Maxilla
What muscles can be seen in the image?
The temporalis muscle
The superficial and deep head of the masseter muscle
What muscles are shown in blue?
The superior and inferior head of the lateral pteryoid muscle
What muscle is shown in green?
The superficial and deep head closer to back of the medial ptery void
What muscle is shown here?
The platysma muscle
What muscle is shown here?
The posterior belly of the digastric muscle
What ligament are shown here?
The stylomandibular ligament
The temporomandibular ligament
The joint capsule
What ligament is shown here?
The sphenomandibular ligament
Describe the orientation of the pharynx, larynx oesophagus and trachea?
What is the boundary between the oral county t the pharynx?
The oropharyngeal isthmus
What bone is shown here?
Palatine bone
What different bones make up the oral cavity?
The unpaired: sphenoid, hyoid and mandibular
The paired: Maxillary, temporal and palatine
What is the orange label?
The incisive fossa
What is the green label?
The palatine process of the maxilla
What is the pink lable?
Alveolar process of maxilaa
What is the blue label?
Horizontal process of the palatine
What is the red line?
The transverse suture (between the maxilla and the palatine bone)
What makes up the purple label?
The greater and lesser palatine foramen
What makes up the red labels?
The medial and lateral pterygoid plate
What is the black label?
The pterygoid hamulus
What is the pterygoid fovea?
A small depression on the surface of the anterior neck of the mandible for attachment of the inferior head of the lateral pterygoid muscles
Label the features of the mandible
Coronoid process
Alveolar arch
Mental foramen
Body
Angle
Ramus
Condylar process
What is the genial tubercule of the mandible?
Made of 4x mental spines 2x superior and two inferior, just lateral to the midline on the posterior mandible
Provide a point of attachment for the genioglossus and the geniohyoid muscles
What is the black label?
The lingula
What is the purple label?
The submandibular fossa
What is the pink label?
mylohyoid line
What is the blue label?
The sublingual fossa
What is the red label?
The superior and inferior mental spines
What are the boundaries of the buccinator muscle?
‘the cheeks’
Fuses with the orbicularis oris muscle anteriorly and fuses with muscles of the pharynx posteriorly.
Forms attachment with the alveolar process of the mandible and the maxillary bones.
What are the geniohyoid muscles?
Paired muscles from the inferior mental spines to the anteror hyoid bone.
Superior to mylohyoid
Make up floor of oral cavity
Pull the hyoid superior and propulsion for swallowing
When hyoid bone is fixed can help depress the mandible to open the mouth
What are the mylohyoid muscles?
Paired muscle
Form the muscular inferior limit of the floor of the oral cavity
Originate from the mandible and infert onto hyoid bone
Supports and elevates the oral floor
Depress mandible when hyoid fixed to aid opening of the mouth
Elevate and propulse the hyoid to help open the mouth
What are the label missing from this sagittal section of the mouth?
The mandible
THe genohyoid
The mylohyoid
The hyoid bone
The root of the tongue
The terminal sulcus
What are the four intrinsic muscles of the tongue?
The superior longitudinal
The vertical
The transverse
The inferior longitudinal
The septum (sort of)
What is the function of the intrinsic muscles of the tongue?
Lengthen and shorten the tongue
Curla dn uncurl the edges and apex
Flattening and rounding is surface
What are the four extrinsic muscles of the tongue?
Palatoglossus
Styloglossus
Hypoglossus
Genioglossus
What muscles are shown here?
Master posteriorly and buccinator anteriorly
What muscle is shown here?
Geniohyoid muscle
What muscle is shown? Green arrow
Mylohyoid
What muscle is shown here?
Platoglossus
What muscle is shown here?
Styloglossus
What muscle is shown here?
Genioglossus
What muscle is shown here?
Hyoglossus
The four extrinsic muscles of the tongue attach to the tongue and what other structures?
Genioglossus - superior genial tubercule of mandible
Hypoglossus - hyoid bone
Palatoglossus - soft palate
Styloglossus - styloid process
What is the action of the genioglossus muscle why is this important to cranial nerve testing?
Is innervated by hypoglossal nerve.
Protrudes the tongue anteriorly and deviates the tongue to the opposite side.
If not functional the tongue will lie on fall towards the no-functional side of the mouth
Identify the muscles of the extrinsic tongue?
Green - styloglossus
Blue - palatoglossus
Pink - hyloglossus
Yellow - genioglossus
What is the general structure of the sublingual gland?
Deep to the tongue
Bordered laterally by the mandible and medially by the genioglossus muscle of the tongue
Sits in the sublingual fossa
What nerve passes through the parotid gland but does not innervate it?
Cranial nerve 7 - facial nerve
Draw a diagram to represent innervation of the tongue?
What are the two different types of movement within the TMJ joint?
Pivoting and Translation
What is articular disc displacement?
The mandible and articular disk are protracted
But only the mandible is retracted and the articular disc moves forward potentially in front of the articular tubercule
Condyle can press on innervated tissue causing pain and jaw movement is restricited
What is the function of the masseter muscle?
Deep head - vertical fibres from the deep zygomatic arch - ONLY elevates the mandible
Superficial head - oblique fibres - elevate and protract the mandible
