Orofacial Anatomy and Cranial Nerve Innervation

Comprehensive vocabulary flashcards covering cranial nerves, trigeminal branches, local anesthesia blocks, salivary glands, and neuroanatomy.

Olfactory Nerve (CN I)

An afferent cranial nerve that transmits the sense of smell from the nasal mucosa to the brain.

Optic Nerve (CN II)

An afferent cranial nerve that transmits sight signals from the retina of the eye to the brain.

Oculomotor Nerve (CN III)

An efferent cranial nerve that passes through the superior orbital fissure to innervate eye muscles, including the superior rectus, inferior rectus, medial rectus, and inferior oblique.

Trochlear Nerve (CN IV)

An efferent cranial nerve with no parasympathetic component that exits through the superior orbital fissure to innervate the superior oblique eye muscle and convey proprioception.

Trigeminal Nerve (CN V)

A mixed cranial nerve containing efferent fibers to the muscles of mastication and cranial muscles, and afferent fibers supplying the teeth, tongue, oral cavity, and most of the skin of the face and head.

Abducens Nerve (CN VI)

An efferent cranial nerve that enters through the superior orbital fissure to innervate the lateral rectus muscle and move the eyeball.

Facial Nerve (CN VII)

A mixed cranial nerve providing efferent motor innervation to muscles of facial expression, visceral parasympathetic fibers to the lacrimal and submandibular/sublingual glands, and afferent taste sensation to the anterior two-thirds of the tongue.

Vestibulocochlear Nerve (CN VIII)

An afferent cranial nerve that conveys sensory signals from the inner ear to the brain for hearing and balance.

Glossopharyngeal Nerve (CN IX)

A mixed cranial nerve that motor innervates the stylopharyngeus muscle, provides parasympathetic secretomotor fibers to the parotid gland via the otic ganglion, and supplies afferent taste and general sensation to the posterior third/base of the tongue.

Vagus Nerve (CN X)

A mixed cranial nerve exiting via the jugular foramen that supplies efferent fibers to the muscles of the soft palate, pharynx, larynx, and thoracic/abdominal viscera, as well as afferent fibers to the skin around the ear and epiglottis taste sensation.

Spinal Accessory Nerve (CN XI)

An efferent cranial nerve that innervates the trapezius and sternocleidomastoid muscles and assists the tenth cranial nerve.

Hypoglossal Nerve (CN XII)

An efferent cranial nerve that exits through the hypoglossal canal in the occipital bone to innervate the intrinsic and extrinsic muscles of the tongue.

Ophthalmic Nerve ($V_1$)

The first division of the trigeminal nerve; a purely afferent nerve that enters the skull via the superior orbital fissure to carry somatic sensation from the forehead, scalp, upper eyelid, nose, cornea, and lacrimal gland.

Maxillary Nerve ($V_2$)

The second division of the trigeminal nerve; a purely afferent nerve that passes through the foramen rotundum to carry somatic sensation from the cheek, lower eyelid, upper lip, nasal mucosa, palate, and upper teeth.

Mandibular Nerve ($V_3$)

The third division of the trigeminal nerve; a mixed nerve entering through the foramen ovale that carries efferent motor fibers to the muscles of mastication and afferent sensory fibers from the chin, temporal scalp, anterior tongue, and lower teeth.

Stylopharyngeus Muscle

A pharyngeal muscle innervated by the efferent branch of the glossopharyngeal nerve (CN IX) that functions to elevate the pharynx during swallowing.

Chorda Tympani Nerve

A branch of the facial nerve (CN VII) that carries parasympathetic efferents to the submandibular and sublingual salivary glands and conveys afferent taste sensation from the anterior two-thirds of the tongue.

Greater Petrosal Nerve

A branch of the facial nerve that arises before exiting the skull, carrying preganglionic parasympathetic efferent fibers to the pterygopalatine ganglion to innervate the lacrimal gland.

Posterior Superior Alveolar (PSA) Nerve Block

A local anesthetic technique that anesthetizes the maxillary molars and associated buccal periodontium and gingiva within one maxillary quadrant.

Middle Superior Alveolar (MSA) Nerve Block

An injection that anesthetizes the maxillary premolars and associated buccal periodontium and gingiva within one maxillary quadrant.

Anterior Superior Alveolar (ASA) Nerve Block

An injection that anesthetizes the maxillary anterior teeth and associated labial periodontium and gingiva to the midline within one maxillary quadrant.

Infraorbital Nerve Block

A nerve block that anesthetizes the maxillary anterior teeth and premolars, along with their facial periodontium and gingiva, covering the combined distribution of both the ASA and MSA nerves.

Greater Palatine Nerve Block

An injection that anesthetizes the periodontium and gingiva of the maxillary posterior teeth within one maxillary posterior sextant.

Nasopalatine Nerve Block

An injection providing bilateral anesthesia to the palatal periodontium and gingiva of the maxillary anterior teeth from canine to canine within the maxillary anterior sextant.

Anterior Middle Superior Alveolar (AMSA) Nerve Block

A single-site palatal injection that anesthetizes a large area innervated by the ASA, MSA, nasopalatine, and greater palatine nerves within the maxillary arch.

Inferior Alveolar (IA) Nerve Block

A nerve block that anesthetizes mandibular teeth, lingual periodontium and gingiva to the midline, and facial periodontium and gingiva of mandibular anterior teeth and premolars to the midline.

Buccal Nerve Block

An injection that anesthetizes the skin of the cheek, buccal mucosa, and associated buccal periodontium and gingiva of the mandibular molars.

Gow-Gates Mandibular Nerve Block

An injection technique that anesthetizes the entire mandibular nerve ($V_3$) within one quadrant, commonly used when clinical effectiveness of the inferior alveolar block fails.

Vazirani-Akinosi Mandibular Nerve Block

A closed-mouth mandibular block covering a large area similar to the IA nerve block, recommended for patients with severe trismus or difficulty opening.

Mental Nerve Block

An injection that anesthetizes the mental nerve, supplying facial periodontium and gingiva of mandibular anterior teeth and premolars to the midline, the lower lip, and the chin.

Incisive Nerve Block

An injection anesthetizing the mental and incisive nerves, mandibular anterior teeth and premolars, labial/facial gingiva to the midline, and lower lip/chin, without providing lingual anesthesia.

Bell Palsy

A condition characterized by unilateral facial paralysis of no known cause, stemming from a loss of excitability of the involved facial nerve (CN VII).

Trigeminal Neuralgia

A sensory nerve disorder typically involving unilateral sharp, short-term facial pain along the maxillary ($V_2$) or mandibular ($V_3$) distributions triggered by touch, speaking, or chewing.

Parotid Salivary Gland

The largest major salivary gland, producing approximately $25\%$ of total salivary volume solely as serous secretions; innervated parasympathetically by CN IX via the otic ganglion and drained by Stensen's duct.

Sublingual Salivary Gland

The smallest, unencapsulated major salivary gland, contributing roughly $10\%$ of total salivary volume mainly as mucous secretions; drained by Bartholin's duct.

Submandibular Salivary Gland

The primary contributor to total salivary volume at approximately $60\%$ to $65\%$, producing mixed serous and mucous secretions; drained by Wharton's duct.

Von Ebner Salivary Glands

Minor salivary glands associated with the base of the circumvallate lingual papillae on the dorsal surface of the posterior tongue that secrete exclusively serous saliva directly through short, unnamed ducts.

Thyroid Gland

The largest endocrine gland; secretes thyroxine directly into the bloodstream to regulate the body's metabolic rate.

Goiter

An enlarged, palpably firm or tender thyroid gland that may contain hard masses, partially visible during extraoral examination.

Hashimoto Thyroiditis

An autoimmune disorder attacking the thyroid gland causing hypothyroidism; childhood manifestations include enlarged tongue and lips, delayed tooth eruption, and enamel hypoplasia.

Graves Disease

An autoimmune hypertrophy of the thyroid gland causing hyperthyroidism and thyroxine hypersecretion; signs include exophthalmos, tachycardia, weight loss, tremors, heat intolerance, and accelerated tooth eruption.

Thymus Gland

An endocrine and lymphoid organ where T-cell lymphocytes mature in response to thymic hormone stimulation to fight disease.

Parathyroid Glands

Ductless endocrine glands that produce and secrete parathyroid hormone directly into the vascular system to regulate calcium and phosphorus levels.

Neuron

The cellular functional component of the nervous system consisting of a neural cell body, dendrites, and an axon.

Axon

A long, thin, cable-like cytoplasmic process of a neuron that conducts impulses away from the neural cell body.

Dendrite

A thread-like process with multiple branches that receives and conducts neural impulses toward the cell body.

Synapse

The junction between two neurons or between a neuron and an effector organ where neural impulses are transmitted via chemical neurotransmitters.

Ganglion

An accumulation of neuron cell bodies situated outside the central nervous system within the peripheral nervous system.

Nerve Fascicles

Bundles or tracts of nerve fibers enclosed together within a peripheral nerve.

Mantle Bundles

Nerve fibers located in the outermost part of nerve fascicles that innervate proximal structures; they are exposed earlier to higher concentrations of anesthetic and anesthetize more rapidly.

Core Bundles

Nerve fibers located in the innermost part of nerve fascicles that innervate distal structures; they are exposed later to lower anesthetic concentrations and take longer to anesthetize.

Resting Potential

The unequal distribution of electrical charges across an unexcited cell membrane, measured in millivolts, where the outer fluid is positive and the inner fluid is negative.

Action Potential

A brief, temporary reversal of electrical charge across a nerve membrane lasting less than a millisecond, initiated when sodium channels open to let sodium ions rush inward.

Sympathetic Nervous System

A division of the autonomic nervous system responsible for 'fight-or-flight' responses, leading to conditions such as hyposalivation and dry mouth (xerostomia).

Parasympathetic Nervous System

A division of the autonomic nervous system governing 'rest-or-digest' responses, stimulating salivary gland secretion to aid digestion.