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LOCAL ANESTHESIA FOR THE DENTAL HYGIENIST:. Anatomy Review. Main Structures Involved:. Facial Bones of the Skull : -Maxilla, Mandible, and Palatine bones Cranial Nerve V—Trigeminal nerve : V2-Maxillary branch of the Trigeminal nerve V3-Mandibular branch of the Trigeminal nerve.
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LOCAL ANESTHESIA FOR THE DENTAL HYGIENIST: Anatomy Review
Main Structures Involved: Facial Bones of the Skull: -Maxilla, Mandible, and Palatine bones Cranial Nerve V—Trigeminal nerve: V2-Maxillary branch of the Trigeminal nerve V3-Mandibular branch of the Trigeminal nerve
Cranial Nerves • Emerge from the inferior surface of the brain • All pass through the foramina (window like opening) of the skull to innervate structures in the head, neck, and facial region
Cranial Nerves (12 pairs) • I- Olfactory • II- Optic • III- Oculomotor • IV- Trochlear • V- Trigeminal • VI- Abducent • VII- Facial • VIII-Vestibulocochlear • IX- Glossopharyngeal • X- Vagus • XI- Accessory • XII- Hypoglossal
Trigeminal NerveLargest cranial nerve/Most Important • Short trunk from brain with 2 roots • Afferent /Sensory Root [larger] • Has trigeminal ganglion • Opthalmic V1 • Maxillary V2 • Mandibular V3 • Motor /Efferent root [smaller] • Muscles of mastication • Parasympathetic to salivary glands
Cranial Nerve V (Trigeminal) • 3 Divisions/branches • V1 entirely afferent • V2 entirely afferent • V3 mixed, both afferent and efferent
V-1 Ophthalmic Division • Enters the eye through the Superior orbital fissure • Sensation to conjuctiva, cornea, eyeball, orbit, forehead, ethmoid sinus, frontal sinus, dura mater of brain
V-2 Maxillary Division • Enters the skull through the Foramen Rotundum Afferent (Sensory) nerve for: • Maxilla and overlying skin and dental plexus • Maxillary sinuses • Nasal cavity • Palate • Nasopharynx • Part of dura mater
V2 Branches:Infraorbital Nerve • Sensation for upper lip, medial cheek, lower eyelid and side of the nose • Passes through infraorbital sulcus (groove in floor of orbit) becomes: • Infraorbital canal which terminates at: • Infraorbital foramen
V2 Branches:Anterior Superior Alveolar (ASA) • Sensation for Maxillary centrals, laterals, canines, and associated tissues • Originates in pulp tissues of teeth at apical foramen • Joins the infraorbital nerve along anterior wall of maxillary sinus • May cross over midline.
V2 Branches:Middle Superior Alveolar (MSA) • Sensation for Maxillary premolars and mesiobuccal root of the 1st molar, and buccal gingiva. • Originates in pulp tissues of teeth at apical foramen • Joins the infraorbital nerve along lateral wall of maxillary sinus • Not present on all patients. • Communicates with ASA and PSA nerves.
V2 Branches:Posterior Superior Alveolar (PSA) • Sensation for Maxillary 1st (except MB root), 2nd, 3rd molars, buccal gingiva, and maxillary sinus. • Originates in pulp tissues of teeth at apical foramen • Joins the infraorbital nerve along lateral wall of maxillary sinus • Communicates with ASA and MSA nerves.
V2 Branches: Greater Palatine Nerve • Posterior hard palate and posterior lingual gingiva • Enters Greater palatine foramen near 2-3rd molar
V2 Branches: Lesser Palatine Nerve • Soft Palate and palatine tonsillar tissues • Enters lesser palatine foramen near pterygoid process
V2 Branches: Nasopalatine Nerve • Mucosa of anterior hard palate and lingual gingiva of maxillary teeth • Enters incisive foramen beneath incisive papilla • Travels along nasal septum • Communicates with GP nerve lingual to the maxillary canines
V-3 Mandibular Division • Enters the skull through the Foramen Ovalein Sphenoid bone • Largest of three divisions • Sensory root to: • Cheek • External ear and scalp • Tongue • Submand/Sublingual salivary glands • Floor of the mouth • Mandibular dental plexus • Motor root to: • Muscles of Mastication • Palatal muscles
V3 Branches: Buccal Nerve • Skin of cheek • Buccal mucosa • Buccal gingiva of mandibular posterior teeth Located on surface of buccinator muscle
V3 Branches: Lingual Nerve • Lateral surface of the tongue • Slightly medial to Inferior alveolar nerve • Sensory for body of the tongue, floor of the mouth, and lingual gingiva of mandibular teeth
V3 Branches: Mental Nerve • Sensory for chin, lower lip, and labial mucosa of mandibular pre-molars, and anterior teeth • Merges with the incisive nerve to form the IA nerve • Enters the mental foramen on the anterior surface of the mandible near 1st and 2nd premolar apices
V3 Branches: Incisive Nerve • Sensory for mandibular premolars and anterior teeth pulp tissue • Merges with the mental nerve to form the IA nerve • May crossover midline • Enters the mental foramen on the anterior surface of the mandible near 1st and 2nd premolar apices
V3 Branches: Inferior Alveolar Nerve • Sensory for mandibular teeth • Formed from merger of the mental and incisive nerves • Exits the mandibular foramen on the lingual surface of the ramus
V3 Branches: Mylohyoid Nerve • Efferent (motor) for mylohyoid muscle and anterior belly of digastric muscle • May serve as a afferent nerve for mandibular 1st molar if IA nerve block failure