Lecture 6 - Muscles of Mastication & Neck-1 PDF

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COMMONWEALTH OF AUSTRALIA Copyright Regulation WARNING This material has been reproduced and communicated to you by or on behalf of the University of Sydney in accordance with section 113P of the Copyright Act 1968 (Act). The material in this communication may be subject to copyright under the Act. Any further reproduction or communication of this material by you may be the subject of copyright protection under the Act. Do not remove this notice The University of Sydney Page 1 Lecture 4 Muscles of Mastication & Neck Dr Filip Vujovic DDS, PhD Slides: Dr Jonathan D. Hakim School of Medical Sciences The University of Sydney Lithograph by Battistelli after Costantino Squanquerillo, 1836 The University of Sydney Page 2  Learning Objectives Muscles of the head and neck – Locate and identify muscles of the head and neck. – Identify the muscles responsible for facial expression and mastication. – Identify muscles of the tongue – Identify muscles of the neck – Describe the origin, insertion and action of muscles of the head and neck. The University of Sydney Page 3  Definitions Mastication: the process of chewing solid food into small pieces in preparation for swallowing and digestion. – Stimulates saliva production – Contributes to taste & smell – Aids digestion Swallowing: also known as deglutition, is the process of clearing the oral cavity of saliva and transporting ingested food or liquid to the oesophagus. The University of Sydney Page 4  Muscles of Mastication – A group of muscles responsible for the chewing movements of the mandible at the temporomandibular joint (TMJ). – Primary Muscles: temporalis, masseter, lateral pterygoid, medial pterygoid – Accessory Muscles: digastric muscle, buccinator, supra- and infra-hyoid muscles The University of Sydney Page 5  Temporomandibular Joint (TMJ) The TMJ is a synovial joint comprised of: Articular surfaces – Head of the condyle of the mandible – Mandibular/glenoid/articular fossa and articular tubercle of temporal bone – Articular disc Stabilising structures – Joint capsule and lateral ligament (attached to zygomatic arch and neck of the condyle) – Postglenoid tubercle (posterior to mandibular fossa and petrotympanic fissure) – Stylomandibular ligament (from styloid process to angle of the mandible) – Derived from posterior portion of the parotid capsule – Sphenomandibular ligament (from spine of the sphenoid to the lingula of the mandible) The University of Sydney Page 6  Temporomandibular Joint (TMJ) – Bony parts Head and neck of mandible Temporal Bone 45. Articular 26. Articular 27. 43. Postglenoid tubercle fossa Petrotympanic tubercle fissure The University of Sydney Page 7  Temporomandibular Joint (TMJ) – Stabilising Structures Inferior alveolar 5. Sphenomandibular ligament Joint capsule & lateral ligament nerve 6. Stylomandibular ligament The University of Sydney Angle of mandible Lingula Page 8  Temporomandibular Joint (TMJ) – Movements Ginglymoarthrodial joint – Hinging (ginglymus) and sliding (athroidial) joint – Depression (opening the mouth) – Elevation (closing the mouth) – Reverse to movement opening – Protrusion (forward movement) – Anterior slide – Retrusion (backward movement) – Return resting position after protrusion – Lateral movement (limited by joint capsule and lateral ligament) The University of Sydney Page 9 Muscles of Mastication Superior temporal line - Superior attachment of the MASSETER MUSCLE temporalis fascia Superficial Head Origin: Inferior border of the anterior 2/3 of zygomatic arch and maxillary Inferior temporal line process of zygomatic bone Insertion: Angle of mandible, inferior and lateral ramus TEMPORALIS MUSCLE Origin: Temporal fossa, along Deep Head inferior temporal line Origin: Medial border of zygomatic Vertical fibres Horizontal fibres Insertion: Coronoid process, arch, inferior border of posterior 1/3 anterior border of the ramus of zygomatic arch Insertion: Superior and lateral ramus, coronoid process Actions Elevation (vertical fibres), Retrusion (horizontal fibres) Actions Elevation, Protrusion (superficial head) The University of Sydney Page 10 MASSETER MUSCLE Temporalis muscle Vertical fibres Temporalis fascia Horizontal fibres Tendon Deep Superficial Masseter muscle The University of Sydney Page 11 TEMPORALIS MUSCLE Temporalis muscle Tendon Zygomatic arch (cut) 12. Coronoid process Masseter muscle (cut) The University of Sydney Page 12 Muscles of Mastication LATERAL PTERYGOID MEDIAL PTERYGOID Upper Head Deep Head Origin: Infratemporal surface of Origin: Medial surface of lateral sphenoid pterygoid plate Insertion: Capsule of TMJ, anterior Insertion: Medial ramus and and medial portions of articular disc, angle of mandible Upper Neck of mandible Superficial Head Lower Head Lower Origin: Pyramidal process of Origin: Lateral surface of lateral palatine bone and maxillary pterygoid plate tuberosity Superficial Insertion: Neck of the condyle of Insertion: Medial ramus and mandible (pterygoid fovea) angle of mandible Actions TMJ Capsule Actions Depression, Protrusion and Lateral Elevation, Protrusion, Lateral movements movements The University of Sydney Page 13 Muscles of Mastication LATERAL PTERYGOID MEDIAL PTERYGOID Upper Head Deep Head Origin: Infratemporal surface of Origin: Medial surface of lateral sphenoid pterygoid plate Insertion: Capsule of TMJ, anterior Insertion: Medial ramus and and medial portions of articular disc, Upper (Upper Head) angle of mandible Neck of mandible Superficial Head Lower Head Lower Origin: Pyramidal process of Origin: Lateral surface of lateral Deep palatine bone and maxillary pterygoid plate tuberosity Insertion: Neck of the condyle of Superficial Insertion: Medial ramus and (Lower Head) mandible (pterygoid fovea) angle of mandible Actions Actions Depression, Protrusion and Lateral Elevation, Protrusion, Lateral movements movements The University of Sydney Page 14  Upper head (lateral pterygoid) 7. Articular disc 10. Lower head (lateral pterygoid) 15. Deep head (medial pterygoid) Superficial head (medial pterygoid) 16. Parotid duct 17. Buccinator muscle 13. Masseter (cut) The University of Sydney Page 15 The University of Sydney Page 16 Muscles & Triangles of the Neck The University of Sydney Page 17  Superficial Muscles of the Neck STERNOCLEIDOMASTOID Attachments – from sternum & clavicle, to mastoid process (temporal bone) Function – tilts & rotates the head (single) flexes head and raises sternum (paired) TRAPEZIUS Attachments – external occipital protuberance & superior nuchal line to ligamentum nuchae, spinous processes of T12, clavicle & scapula Function – moves shoulder and scapula. Extends the head. The University of Sydney Page 18  Triangles of Neck Triangles are regions of anterior & lateral neck, used to describe location of key features in the neck. The University of Sydney Page 19  S Triangles of Neck P A I Mandible P o st. Belly of D igas s tric t iga ric lly of D. Be An t S te rn Trapezius oid oc hy lei mo O do of lly ma Be p. line Su s to id M id d m o hyoi fO B e lly o Inf. Clavicle The University of Sydney Page 20  S Triangles of Neck P A I Mandible P o st. Belly Digastric of D igas s tric t iga ric of D lly. Be An t S te Submental Carotid rn Trapezius oid oc hy lei mo O do of lly ma Be Occipital p. line Su Muscular s to id M id d m o hyoi fO ar B e lly o c l a v i cu l Inf. Sup ra Clavicle The University of Sydney Page 21  Triangles of Neck Neurovascular bundle Internal Jugular, Carotids & Vagus Submandibular Gland P o st. Suprahyoid Muscles Belly of D igas ga stric t ric o f Di elly n t. B S te A rn Accessory Nerve oid oc hy lei mo O do of lly ma Be p. Su s to id d m o hyoi Thyroid fO Gland B e lly o Inf. Infrahyoid Muscles The University of Sydney Page 22  Muscles of the Neck – Anterior/Lateral Suprahyoid Muscles - Digastric - Mylohyoid - Stylohyoid - Geniohyoid Infrahyoid Muscles - Omohyoid - Thyrohyoid - Sternohyoid - Sternothyroid The University of Sydney Page 23  Posterior Triangle Muscles in floor of posterior triangle: – Splenius capitus muscle – Levator scapulae muscle – Scalene muscles (poster, middle, anterior) The University of Sydney Page 24  Question Which muscle divides the anterior and posterior triangle of the neck? A. Omohyoid B. Trapezius C. Sternocleidomastoid D. Scalene muscles The University of Sydney Page 25