OCB04-2006 Mast TMJ Swallowing_Revision_Answers.docx
Transcript
Practical Revision/Summary notes Mastication, TMJ and Swallowing: The TMJ cavity is divided by the articular disc It allows for 6 types of movements: lateral deviation, protusion, retrusion, elevation and depression Gliding: upper compartment between moving disc and stationary fossa Hinge: lower com...
Practical Revision/Summary notes Mastication, TMJ and Swallowing: The TMJ cavity is divided by the articular disc It allows for 6 types of movements: lateral deviation, protusion, retrusion, elevation and depression Gliding: upper compartment between moving disc and stationary fossa Hinge: lower compartment between moving condyle and stationary disc Infratemporal fossa: space found posterior to the maxilla and deep to both the zygomatic arch plus ramus of mandible. The fossa allows the passage of: Some muscles of mastication, namely temporalis and pterygoid The maxillary artery The pterygoid plexus of veins Muscles of mastication VAN: Venous drainage is via the pterygoid plexus, which drains into the maxillary vein, although also anastomoses with the facial vein Arterial supply is via the maxillary artery, the larger of the terminal branches from the external carotid Innervation is via the anterior trunk of the mandibular nerve ** Add this information to the table / sketch from the previous summary notes:** Mandibular nerve – supplies muscles of mastication in addition to the muscles and mucosa of floor as well as buccinator (cheek). I.e. most of the structures that surround or neighbour the mandible is targeted by this nerve Maxillary artery – provides blood to the muscles of mastication, as well as the buccinator (cheek) muscle, seeing how these are neighbours Now fill in the following table outlining the origin and insertion of the 4 (major) muscles of mastication covered in the video lecture: Muscle Origin Insertion Action Masseter Zygomatic arch/bone Ant border of angle and ramus of mandible Elevation, retrusion and ipsilat excursion Temporalis Side of skull, mostly temporal bone Coronoid process of mandible Elevation, retrusion; ipsilat excursion; Tonus Medial pterygoid Medial surface of the lateral pterygoid plate Ramus and angle of the mandible Elevation, protrusion and contralat excursion Lateral pterygoid Lateral pterygoid plate and sphenoid bones Condyle of the mandible Depresstion, protrusion and contralat excursion Swallowing This action involves moving the pharynx (and larynx) upwards, while also opening its lumen. Movement of the pharynx implies moving the hyoid bone. Raising the pharynx – by contracting the suprahyoid muscles while stabilizing the mandible Depressing the Pharynx – by contracting the infrahyoid and lateral pterygoid muscles The timeline of swallowing consists of 3 main stages: buccal, pharyngeal and oesophageal. Write a short summary of what happens to these structures when swallowing occurs: (or via a diagrammatic sketch) Tongue Soft palate Pharynx Glottis Oesophagus Cardia sphincter of the stomach
