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Surgical anatomy of the temporomandibular joint and surgical (nx power lite) /certified fixed orthodontic courses by Indian dental academy
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Surgical anatomy of the temporomandibular joint and surgical (nx power lite) /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

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Surgical anatomy of the temporomandibular joint and surgical (nx power lite) /certified fixed orthodontic courses by Indian dental academy Surgical anatomy of the temporomandibular joint and surgical (nx power lite) /certified fixed orthodontic courses by Indian dental academy Presentation Transcript

  • SURGICAL ANATOMY AND APPROACHES TO THE TEMPOROMANDIBULAR JOINT INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  •          INTRODUCTION OF THE TMJ ARTICULATORY SYSTEM TMJ CAPSULE ARTICULAR DISK LIGAMENTS BLOOD AND NERVE SUPPLY MUSCLES MOVEMENTS OF THE TMJ SURGICAL ANATOMY www.indiandentalacademy.com
  • INTRODUCTION  The TMJ is also known as the craniomandibular joint/articulation. www.indiandentalacademy.com
  •   The TMJ is a gingylmoarthrodial joint that is freely mobile with superior and inferior joint cavities separated by the meniscus (articular disc). It is considered as a complex joint because it involves two separate joints (rt. & lt.) in which there is presence of intracapsular disc and both joints have to function in coordination. www.indiandentalacademy.com
  • ARTICULATORY SYSTEM       The articulatory system comprises of the following : The TMJ The masticatory and accessory muscles The occlusion of the teeth. The function is governed by sensory and motor branches of he third division of the trigeminal nerve (mandibular) and a few fibers of the facial nerve. The occlusion of the teeth plays an imp. role in he function of the TMJ. Normally, the greatest part of the force of mastication is borne by the dentition of the jaws, but in case of occlusal disharmony, a great deal of force can be shifted to the joint itself. www.indiandentalacademy.com
  • CRANIAL COMPONENT   Mandibular ( glenoid fossa) : It is an anterior articular area formed by the inferior aspect of temporal squama. It’s surface is smooth, oval and deeply hollow and the bone is very thin at the depth of the fossa. The fossa is lined by dense avascular fibrocartilage. www.indiandentalacademy.com
  • CRANIAL COMPONENT       Limits are : Anteriorly – articular eminence or tubercle Posteriorly – post glenoid tubercle Medially – spine of he sphenoid bone Laterally – root of the zygomatic process of temporal bone Superiorly – separated from MCF by thin plate of bone at apex www.indiandentalacademy.com
  • MANDIBULAR COMPONENT   Mandibular condyle : The articular part of the mandible is an ovoid condylar process (head) with narrow mandibular neck. It is broad laterally and narrower medially. The articular part of the condyle is covered by fibrocartilage. www.indiandentalacademy.com
  • MANDIBULAR COMPONENT       Mediolateral dimension varies bn. 13 – 25 mm. Anteroposterior width varies bn. 5.5 – 16 mm. Majority of the human condyles (58%) are slightly convex superiorly. 25% of the condyles may be flat superiorly. 12% are pointed or angular in shape. 3% are bulbous or rounded in shape. www.indiandentalacademy.com
  • TMJ CAPSULE    TMJ capsule is a thin sleeve of fibrous tissue investing the joint completely, it defines the anatomic and functional boundaries of the TMJ. It is a funnel shaped capsule, which blends with the periosteum of the mandibular neck and it envelops the articular disc. On the temporal bone, the articular capsule surrounds the articular surfaces of the eminence and fossa. www.indiandentalacademy.com
  • TMJ CAPSULE  Attachments  Anteriorly – ant. border of the articular eminence. Posteriorly – lip of squamotympanic fissure and ant. sf. of postglenoid pss. Laterally – edge of the eminence and glenoid fossa. Medially – along the sphenosquamosal suture. Below – neck of the condyle medially and laterally.     www.indiandentalacademy.com
  • TMJ CAPSULE     Each part of the joint is surrounded by short capsular fibers which stretch from the condyle to the disc, and from the disc to the temporal bone forming two joint capsules. Longer bands extending from the condyle to the temporal bone may be regarded as reinforcing fibers. Capsular fibers passing bn. the mandible and temporal bone are present only on the lateral side. The cavities are lined with synovial tissue with villi extending from anterior and posterior part of the articular disk to the attachments to the temporal bone and mandibular condyle. www.indiandentalacademy.com
  • ARTICULAR DISK    The articular disk, an oval plate of fibrous tissue shaped like a tweaked cap, completely divides the articular space into two compartments: The inferior compartment – condylodiscal complex between the condyle and the disc. The superior compartment – temporodiscal complex between the disc and the glenoid fossa. www.indiandentalacademy.com
  • ARTICULAR DISK   The disk is biconcave in the sagittal section. The superior surface is concavoconvex to match the anatomy of the glenoid fossa and the inferior surface is concave to fit over the condylar head. Histologically the disk is a meshwork of firmly woven avascular fibrous connective tissue. www.indiandentalacademy.com
  • ARTICULAR DISK    The disc is a complex structure. It has three different zones (Rees 1954) posterior band, intermediate band and anterior band. The disk blends medially and laterally with the capsule, which is attached to the medial and lateral poles of the condyle. www.indiandentalacademy.com
  • ARTICULAR DISK   The meniscus projects anteriorly to form a footshaped process the pes meniscus. This pss. is attached superiorly to the articular eminence and superior belly of the lat. pterygoid muscle. Inferiorly the pes meniscus is attached to the articular margin of the condyle. www.indiandentalacademy.com
  • ARTICULAR DISK   The posterior meniscus attachment is the bilaminar zone, composed if two strata of fibres separated by a central zone composed of loose areolar connective tissue. The meniscus is highly vascular in this region and is called the genu vasculosa. ( sensory branches of the auriculotemporal n.) www.indiandentalacademy.com
  • ARTICULAR DISK   The posterior meniscus attaches via the superior stratum (elastic fibers) to the tympanic plate of the temporal bone. The inferior stratum (inelastic collagen) attaches to the neck of the condyle. www.indiandentalacademy.com
  • SYNOVIAL MEMBRANE  The inside of the TMJ capsule and the nonarticulating surfaces of the disk ligaments are lined with synovial membrane.  It has been estimated that the volume of synovial fluid in the superior joint compartment is 1.2ml and in the posterior compartment is 0.9ml.  The synovial fluid contains a glycoprotein known as lubricin, which serves to lubricate and minimize friction between articular surfaces of the joint. www.indiandentalacademy.com
  • TEMPOROMANDIBULAR LIGAMENT   TMJ capsule is reinforced by this main stabilizing ligament. It extends downward and backward from the lat. aspect of the articular eminence to the external and posterior aspect of the condylar neck. This ligament functions like a pendulum, which allows translation but resists abnormal lateral condyle displacement. www.indiandentalacademy.com
  • SPHENOMANDIBULAR LIGAMENT   It is a flat, thin band descending from the spine of the sphenoid and widening to reach the lingula of the mandibular foramen. It is imp. landmark during surgery as the maxillary artery and the auriculotemporal n. lies between it and the mandibule. www.indiandentalacademy.com
  • STYLOMANDIBULAR LIGAMENT  The stylomandibular ligament, a specialized band of deep cervical fascia stretches from the apex and adjacent anterior aspect of the styloid process to the mandible’s angle and posterior border. www.indiandentalacademy.com
  • BLOOD SUPPLY     The lateral aspect is supplied by superficial temporal artery. Rich vascular supply to the deep and posterior aspect of the retrodiscal capsular part by deep auricular, posterior auricular and the masseteric artery. Vascular supply to the lateral pterygoid muscle also supplies the head of the condyle by penetration of numerous nutrient foramina vessels. The venous pattern is more diffuse forming a plentiful plexus all around the capsule. www.indiandentalacademy.com
  • NERVE SUPPLY      The mandibular nerve innervates the TMJ. Three branches from this nerve send terminals to the joint capsule: Largest – Auriculotemporal n. – posterior, medial and lateral parts of the joint. Massseteric nerve. Branch from the posterior deep temporal nerve supplies the anterior parts of the joint. www.indiandentalacademy.com
  • MUSCLES OF MASTICATION    MASSETER : Two heads The superficial head originates on the anterior zygomatic arch, runs downward and backward and inserts on the angle and the ramus. The deep head originates from the posterior part of the zygoma, runs vertically downwards and inserts on the ramus and the coronoid process. www.indiandentalacademy.com
  • MUSCLES OF MASTICATION      TEMPORALIS : Originates from – the lower temporal line, the temporal fossa, temporal fascia. Fibers converge into a tendinous band which then divides into 2 parts. Superficial group of fibers inserts on the superolateral sf. of the coronoid pss. Deeper larger fibers form a band along the inner coronoid pss. extending inferiorly to the ant. border of the ramus. www.indiandentalacademy.com
  • MUSCLES OF MASTICATION     MEDIAL PTERYGOID : Superficial head from tuberosity and adjoining bone. Deep head from medial sf. of lat. Pterygoid plate and palatine bone. Fibers run posteroinferiorly inserting on the medial surface of the ramus and the angle. www.indiandentalacademy.com
  • MUSCLES OF MASTICATION       LATERAL PTRYGOID : Upper head arises from the infratemporal sf. and crest of of the greater wing of the sphenoid. Lower head arises from lat. Pterygoid plate. Fibers run posterolaterally and converge to insert onto: Pterygoid fovea Ant. margin of the articular disc and capsule of the TMJ. www.indiandentalacademy.com
  • ACCESSORY MUSCLES - SUPRAHYOID      DIGASTRIC : The ant. belly originates near the mandibular symphysis. The post. belly originates on the mastoid notch. The ant. belly runs downwards and backward and post. belly forwards to meet the intermediate tendon. This tendon is held by a fibrous pulley attached to the hyoid bone www.indiandentalacademy.com
  • ACCESSORY MUSCLES - SUPRAHYOID    GENIOHYOID : Originates from the genial tubercle and runs backward to insert into anterior surfacef of body of the hyoid. MYLOHYOID : Originates from the mylohyoid line. Fibers run medially and slightly downwards. Post. Fibers insert into body of hyoid. Middle & ant. fibers insert into the median raphe that unites the rt. & lt. muscles. www.indiandentalacademy.com
  • ACCESSORY MUSCLES - SUPRAHYOID  STYLOHYOID : Originates from the post. surface of the styloid process.  The tendon divides into two slips that pass on either sides of the digastric tendon to insert into the hyoid bone. www.indiandentalacademy.com
  • ACCESSORY MUSCLES - INFRAHYOID   STERNOTHYROID : Originates on the manubrium of the sternum and inserts at the thyroid cartilage. THYROHYOID :Originates on the thyroid cartilage and inserts on the hyoid bone. www.indiandentalacademy.com
  • ACCESSORY MUSCLES - INFRAHYOID   OMOHYOID :Originates on the superior part of the scapula and inserts at the lateral border of the hyoid bone. STERNOHYOID : Originates on the manubrium of the sternum and inserts on the body of the hyoid bone. www.indiandentalacademy.com
  • MOVEMENTS OF THE TMJ  Motions of the TMJ are manifold. It is a ginglimus, diarthrodial type of joint, as it is capable of rotating around more than one axis and is capable of hinge/rotatory movement and also capable of gliding/translatory movement.  A hinge type of movement takes place in the lower compartment between inferior aspect of the stationary disc and the moving condyle.  Gliding type of movement takes place in the upper compartment between the superior surface of the disc, which moves with the condyle ,and the stationary mandibular fossa and eminence. www.indiandentalacademy.com
  • MOVEMENTS OF THE TMJ  The mandible can be depressed, elevated, protruded or retruded.  Lateral excursions can also be carried out.  There is a variation of normal patterns of motion in different individuals, which are caused by many factors, including the following:  Condyle head size, shape and inclinaiton.  Glenoid fossa depth and angulation.  Articular eminence height and degree of inclination.  Length and laxity of ligaments comprising the joint capsule. www.indiandentalacademy.com
  • MOVEMENTS    Degenerative joint disease state resulting either from local causes or systemic causes. Strength, length, position and tonicity of muscles of mastication and the suprahyoid musculature. Neuromuscular control of the muscles. www.indiandentalacademy.com
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  • MOVEMENTS (CLOSURE)  It is accomplished by the simultaneous contraction of the masseter, medial pterygoid and temporalis muscle of both the sides. www.indiandentalacademy.com
  • MOVEMENTS (DEPRESSION)    Digastric muscle contraction depresses the body of the mandible. This action is assisted by the suprahyoid, sternohyoid, and geniohyoid muscles. The lateral pterygoid is the trigger and contracts to pull the condylar head downward and forward on the articular eminence. www.indiandentalacademy.com
  • MOVEMENTS (PROTRUSION)  Protrusive movement is brought about by equal and simultaneous contracture of the lateral and medial pterygoid muscles. www.indiandentalacademy.com
  • MOVEMENTS (RETRUSION)  Retrusion is brought about by the posterior fibres of the temporalis muscle, assisted by the masseter, digastric and geniohyoid muscles. www.indiandentalacademy.com
  • MOVEMENTS (RIGHT & LEFT LATERAL) www.indiandentalacademy.com
  • FACIAL NERVE   The main trunk of the facial nerve exits from the skull at the stylomastoid foramen. Approximately 1.3 cm of the nerve is visible before it divides into temporofacial and cervicofacial branches. www.indiandentalacademy.com
  • FACIAL NERVE    In the classis article by Al-Kayat and Bramley the distance from the lowest point of the external bony auditory canal to the bifurcation was found to be 1.5 cm to 2.8 cm (mean 2.3 cm) Distance from the post-glenoid tubercle to the bifurcation was 2.4 to 3.5 cm (mean 3.0 cm) The distance from the most anterior concavity of the bony external auditory canal to the most posterior significant temporal branch of the facial nerve was 0.8 to 3.5 cm (mean 2.0 cm) www.indiandentalacademy.com
  • FACIAL NERVE   Knowledge of the distances and the range of the facial nerve branches from fixed bony landmarks within the surgical field alerts the surgeon to the areas of highest risk. During surgery by incising the superficial layer of the temporalis fascia and the periosteum over the arch inside the 8 mm boundary, damage to the branches of the upper trunk can be prevented. www.indiandentalacademy.com
  • FACIAL NERVE    The temporal branch of the facial nerve emerges from the parotid gland and crosses the zygoma under the temporoparietal fascia to innervate the frontalis, the corrugator, the procerus and occasionally a portion of he orbicularis oculi muscle. Post surgical palsy manifests as an inability to raise the eyebrow or wrinkle the forehead and ptosis of the brow. Damage to the zygomatic branch results in temporary or permanent paresis to the orbicularis oculi. (may require temporary patching of the eye to prevent corneal dessication) www.indiandentalacademy.com
  • AURICULOTEMPORAL NERVE    The auriculotemporal nerve supplies sensation to parts of the auricle, the external auditory meatus, the tympanic membrane, and skin in the temporal area. It courses form the medial side of the posterior neck of the condyle and turns superiorly, running over the zygomatic root of the temporal bone. Just anterior to the auricle, the nerve divides into its terminal branches in the skin of the temporal area. www.indiandentalacademy.com
  • AURICULOTEMPORAL NERVE    Damage to this nerve can be prevented during surgery by incising and dissecting in close apposition to the cartilaginous portion of the external auditory meatus. The nerve runs somewhat anteriorly as it courses from lateral to medial. Temporal extension of the skin incision should be located posteriorly so that the main distribution of the nerve is dissected and retracted forward with the flap. www.indiandentalacademy.com
  •   The superficial temporal artery one of the terminal branches of the ECA, begins behind the mandibular condylar neck deep to the parotid gland as it emerges from behind the parotid gland. It crosses over the posterior root of the zygomatic process of the temporal bone and enters the temporal region of the scalp. www.indiandentalacademy.com
  •  The transverse facial artery arises form the base of the superficial temporal artery and runs almost transversely across the face, lying upon the outer surface of the masseter muscle about 1.5 cm below the zygomatic arch but above the parotid duct. www.indiandentalacademy.com
  • LAYERS OF THE TEMPOROPARIETAL REGION  The temporoparietal fascia is the most superficial layer beneath the subcutaneous fat.  This fascia is the lateral extension of the galea and is continuous with the superficial musculoaponeurotic layer (SMAS).  The blood vessels of the scalp run along its superficial aspect closely related to the subcutaneous fat.  The motor nerves run on the deep surface of the temporoparietal fascia. www.indiandentalacademy.com
  •  The temporalis fascia is the fascia of the temporalis muscle.  This fascia arises from the superior temporal line and fuses with the pericranium.  Inferiorly at the level of the superior orbital rim, the temporalis fascia splits into the superficial layer attaching to the lateral border and the deep layer attaching to the medial border of the zygomatic arch.  A small quantity of fat is found in between these two layers and it is sometimes referred to as the superficial temporal fat pad. www.indiandentalacademy.com
  • REFERENCES         GRAY’S ANATOMY – 38 TH EDITIION COLOR ATLAS OF TMJ SURGERY – PETER D. QUINN FONSECA ORAL AND MAXILLOFACIAL SURGERY VOL. 4 – BAYS and QUINN THE TMJ AND RELATED OROFACIAL DISORDERS – BUSH and DOLWICK SURGICAL APPROACHES TO THE FACIAL SKELETON – EDWARD ELLIS THE ANATOMICAL BASIS OF DENTISTRY – LEIBGOTT SURGERY OF THE TMJ. SURGICAL ANATOMY AND SURGICAL INCISIONS – KREUTZIGER (ORAL SURGERY. 58; 637-646, 1984) CLINICALLY ORIENTED ANATOMY – KEITH L. www.indiandentalacademy.com MOORE
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  • POSTERIOR FIBER DRAWS MANDIBLE BACKWARDS www.indiandentalacademy.com
  • ELEVATION OF MANDIBLE www.indiandentalacademy.com
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  • The combinded efforts of the Digastrics and Lateral Pterygoids provide for natural jaw opening. www.indiandentalacademy.com
  • Medial and lateral pterygoid act together to protrude the mandible www.indiandentalacademy.com
  • Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com