0505 - Pharynx - EG Flashcards
Describe the articular surface of the temporo-mendibular joint.
The articular surface of the TMJ extends from the mandibular surface anteriorly onto the anterior tubercle. The head of the mandible rotates and glides during movements of the jaw across this surface.
What ligament normally prevents dislocation of the TMJ?
the spheno-mandibular ligament.
What occurs in a TMJ dislocation?
The TMJ is vulnerable as it glides forward to sit under the articular tubercle when mouth is open wide as it can become dislocated anteriorly in front of the tubercle where it can be manoeuvred back into position by pulling down and pushing back.
What are the four muscles of mastication and which nerve innervates them?
lateral pterygoid muscle, medial pterygoid muscle, temporalis muscle, and masseter muscle, all innervated by V3 (maxillary branch of the trigeminal nerve)
Which muscles are the deep muscles for mastication?
lateral pterygoid and medial pterygoid
Which muscles are the superficial muscles for mastication?
temporalis and masseter
Which muscle of mastication protrudes the mandible?
lateral pterygoid.
Which muscle of mastication only elevates the mandible (but not the most powerful elevator)?
medial pterygoid.
Which muscle of mastication both elevates and retracts the mandible?
temporalis
Which muscle of mastication provides powerful elevation of the jaw?
masseter
What is the action of the lateral pterygoid muscle?
to pull the mandible forward (protraction of the jaw)
What is the action of the medial pterygoid muscle?
elevation of the mandible (but not that powerful an action)
What is the action of the temporalis muscle?
elevation and retraction of the mandible.
What is the action of the masseter muscle?
Very powerful elevation of the jaw.
Which muscles of mastication are involved in elevation?
temporalis, masseter, medial pterygoid.
Which muscle elevates the soft palate and what nerve innervates it?
levator veli palatini (LVP), innervated by XI (via X)
Which muscle tenses the palate and what nerve innervates it?
tensor veli palatini (TVP), innervated by V3
What muscle is used by singers to modulate the position of the soft palate?
tensor veli palatine (TVP)
List the four palatine muscles and their innervation.
palatopharyngeus (XI via X)palatoglossus (XI via X)levator veli palatini (XI via X)tensor veli palatini (V3)
Briefly describe the larynx.
a muscular tube attached to the base of the skull and located posterior to the nasal cavity (nasopharynx), oral cavity (oropharynx), and larynx (laryngopharynx) that continues into the oesophagus. Posteriorly lies the spine.
List the muscles of the larynx and their innervation.
Three pharyngeal constrictors (XI): inferior, middle and inferior constrictors; three longitudinal muscles: palatopharyngeus (XI), salpingopharyngeus (XI), stylopharyngeus (XI)
What nerves supply the sensory innervation of the pharynx
nasopharynx by V2, oropharynx by IX, laryngopharynx by X.
Describe the process of swallowing (the first step within the mouth)
voluntary initiation of swallowing in the mouth as tongue pushes bolus back and back of tongue elevates, soft palate contracts, to activate reflex, palatopharyngeal sphincter closes to prevent bolus from entering nasopharynx.
Describe the process of swallowing (second step within the pharynx)
in the pharynx the hyoid bone and larynx are elevated by suprahyoids, epiglottis depresses to close over the larynx, bolus divides and deviates laterally into the piriform recess, laryngopharynx elevates and cricopharyngeus relaxes.
