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 posterior 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