Session 9: The Mouth Flashcards
Why might an infection deep in the pterygoid region (the infratemporal fossa) be a danger to the eye?
Pterygoid venous plexus lies deep within infratemporal fossa and is connected to the ophthalmic and anterior facial veins. These drain into the cavernous sinus so a pus build up here may cause increased ophthalmic venous pressure or lead to cavernous sinus thrombosis causing paralysis of extraocular muscles.
Explain why the skin, mucous membrane of the lower lip together with the labial alveolar mucosa and the gum are also anaesthetised during an inferior alveolar nerve block?
THe inferior alveolar nerve forms the inferior dental plexus innervating the mandibular teeth, The mental nerve is a branch of the inferior alveolar nerve and this supplies the skin,mucous membranes of the lower lip, the skin of the chin and the vestibular gingiva.
why might the tongue become numb during an inferior alveolar nerve block?
the anaesthesia may spread to the lingual nerve which is a branch of trigeminal and supplies the anterior two thirds of the tongue (general sensation). It lies directly in front of the inferior alveolar nerve.
On clenching the jaw tight, what structure can be palpated lying on the contracted masseter muscle?
The parotid duct. 3/4 of an inch below and parallel to the zygomatic arch
Why might dislocation of the TMJ sometimes occur during yawning or taking very large bites of food?
The jaw is depressed and protruded by the lateral pterygoid muscles. excessive contraction of these may cause the condylar process to click over the articular tubercle. The mandible will displaced antero-superiorly to lie alongside the zygomatic arch.
