Infratemporal fossa Flashcards
What is the boundaries of the temporal fossa?
• Temporal Fossa: shallow depression on side of skull that funnels inferiorly to pass below zygomatic arch & end at base of skull; separated from Infratemporal Fossa by the Infratemporal Crest
o Posterior & Superior= Superior & Inferior temporal lines
o Anterior= Frontal & Zygomatic Bones
o Lateral= Zygomatic Arch
o Inferior= Infratemporal Crest
What is the contents of the temporal fossa?
temporalis muscle fills the temporal fossa
What are the boundaries of the infratemporal fossa?
o Lateral= Ramus & Condyle of Mandible
♣ Features= LINGULA; MANDIBULAR FORAMEN & CANAL
o Medial= Lateral Pterygoid Plate
♣ Features= PTERYGOMAXILLARY FISSURE
o Anterior= Posterior Aspect of Maxilla
♣ Features= ALVEOLAR FORAMINA
o Posterior= Tympanic Plate; Mastoid & Styloid Processes of Temporal Bone; not bony
o Superior= Inferior Surface of Greater Wing of Sphenoid Bone; Squamous Temporal Bones
♣ Features= FORAMEN OVALE; FORAMEN SPINOSUM
o Inferior= Where medial pterygoid attaches to mandible near its angle; open
What are the contents of the infratemporal fossa?
o Contents Inferior part of temporalis muscle; Lateral & Medial Pterygoid; Maxillary Artery and branches; Pterygoid Venous Plexus; Mandibular, Inferior Alveolar, Lingual, Buccal, & Chorda Tympani Nerves; Otic Ganglion
What are the actions of the TMJ?
• TEMPOROMANDIBULAR JOINT (TMJ)= modified hinge-type synovial joint allowing movement in 3 planes
o Actions: Gliding/Excursion (protrusion/retrusion); depression; elevation
What forms the TMJ?
o Bony Articulating Surfaces:
♣ Mandibular Head/Condyle (inferior)
♣ Articular Tubercle of Temporal Bone (superior, anterior)
♣ Mandibular Fossa of Temporal Bone (superior, posterior)
o surrounded by FIBROCARTILAGE (rather than hyaline cartilage) Fibrous Joint Capsule (loose)
o Articular Disc= divides joint cavity into 2 separate synovial compartments; dense fibrous tissue between condyle & mandibular fossa
♣ Biconcave Discthickened posteriorly; less prominent anterior thickening
♣ Upper Compartment= Translatory Movement (Gliding)
♣ Lower Compartment= Hinge Movement
What ligaments stabilize the TMJ?
o Ligaments of TMJ: connect mandible to the cranium
♣ INTRINSIC:
• LATERAL LIGAMENT OF TMJ= thickened portion of joint capsule to prevent posterior & inferior dislocation of joint; strengthens joint
♣ EXTRINSIC:
• STYLOMANDIBULAR LIGAMENT runs from styloid process to angle of mandible; does NOT contribute to strength of joint
• SPHENOMANDIBULAR LIGAMENT runs from spine of sphenoid to lingual of mandible medial to TMJ; check ligament for movement of extension at TMJ
o PRIMARY PASSIVE SUPPORT OF MANDIBLE (active support= muscles of mastication)
What muscles act on the TMJ?
The muscles of mastication produce movement of mandible at TMJ
What nerve provides sensory innervation to this joint and would carry pain if damaged?
♣ AURICULOTEMPORAL NERVE (sensory innervation from CN V3) & SUPERFICIAL TEMPORAL ARTERY (smaller terminal branch of ECA)
• anterior portion also innervated by nerve to masseter & supplied by small muscular branches of maxillary artery
What causes clicking of TMJ?
minor disc displacement or osteoarthritis
Describe dislocation of TMJ
The mandibular head displaces anterior to the auricular tubercle, should be prevented muscles
What is the innervation of the muscles of mastication?
• Muscles of Mastication are innervated by the MOTOR FIBERS OF CN V3 (MANDIBULAR DIVISION OF TRIGEMINAL NERVE)
o all muscles are derivatives of 1st pharyngeal arch
o Nerve to Medial Pterygoid
o Nerve to Lateral Pterygoid
o Nerve to Masseter
o Deep Temporal Nerve
What muscles act to close the mouth?
• MOUTH CLOSURE/ ELEVATION OF MANDIBLE
o Medial Pterygoid (bilateral contraction)
o Temporalis Muscle (anterior fibers; bilateral contraction)
o Masseter Muscle (bilateral contraction)
What muscles act to open the mouth?
• OPEN MOUTH/ DEPRESSION OF MANDIBLE o Lateral Pterygoid (bilateral contraction; inferior heads) ****main assistor o Suprahyoid o Infrahyoid o Platysma ***against resistance *** but really gravity is the main player
What muscles retrude mandible?
o Temporalis Muscle (posterior fibers; bilateral contraction)**main player
o Digastrics
o Geniohyoid
What muscles protrude the mandible?
o Masseter Muscle (bilateral contraction; superficial fibers)
o Lateral Pterygoid (bilateral contraction)*only assists
o Medial Pterygoid (bilateral contraction)