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Question 1General and Oral Anatomy, Histology, and Physiology

Which permanent tooth normally erupts first into the oral cavity?

  1. Maxillary first molar
  2. Mandibular first molar Correct answer.
  3. Mandibular central incisor
  4. Maxillary central incisor

Explanation

The mandibular first molar typically emerges at about 6 years of age, slightly ahead of the mandibular central incisor, which follows at roughly 6 to 7 years. The maxillary teeth erupt later than their mandibular counterparts, so both maxillary options are incorrect.

Question 2General and Oral Anatomy, Histology, and Physiology

Enamel is formed by which cell type?

  1. Odontoblast
  2. Ameloblast Correct answer.
  3. Cementoblast
  4. Osteoblast

Explanation

Ameloblasts are the specialized epithelial cells of the inner enamel epithelium that secrete the enamel matrix and later mineralize it. Odontoblasts produce dentin, cementoblasts produce cementum, and osteoblasts form bone, so none of these can deposit enamel.

Question 3General and Oral Anatomy, Histology, and Physiology

Which muscle elevates the mandible and is considered the strongest elevator of the jaw?

  1. Platysma
  2. Masseter Correct answer.
  3. Digastric
  4. Lateral pterygoid

Explanation

The masseter is a powerful elevator of the mandible and is often described as the strongest jaw-closing muscle relative to its size. The lateral pterygoid and digastric assist in opening or protruding the mandible, and platysma is a muscle of facial expression.

Question 4General and Oral Anatomy, Histology, and Physiology

The parotid duct opens into the oral cavity at which location?

  1. Posterior tonsillar pillar
  2. Lingual surface of the mandible near the premolars
  3. Floor of the mouth beside the lingual frenum
  4. Vestibule opposite the maxillary second molar Correct answer.

Explanation

The parotid duct (Stensen duct) courses forward across the masseter and pierces the buccinator to open in the vestibule opposite the maxillary second molar. The submandibular duct opens at the floor of the mouth beside the lingual frenum, and the sublingual glands open along the sublingual fold.

Question 5General and Oral Anatomy, Histology, and Physiology

Which type of oral epithelium covers the attached gingiva and hard palate?

  1. Orthokeratinized masticatory mucosa Correct answer.
  2. Parakeratinized lining mucosa
  3. Nonkeratinized lining mucosa
  4. Specialized mucosa with taste buds

Explanation

Masticatory mucosa covers surfaces exposed to friction, such as attached gingiva and hard palate, and is orthokeratinized or parakeratinized. Lining mucosa is nonkeratinized and covers flexible regions, while specialized mucosa refers to the dorsal tongue with taste buds.

Question 6General and Oral Anatomy, Histology, and Physiology

Which cranial nerve provides general sensation from the anterior two-thirds of the tongue?

  1. Lingual nerve branch of the trigeminal Correct answer.
  2. Facial nerve
  3. Hypoglossal nerve
  4. Glossopharyngeal nerve

Explanation

General sensation from the anterior two-thirds of the tongue travels via the lingual nerve, a branch of the mandibular division of the trigeminal nerve. Taste from this region is carried by the chorda tympani of the facial nerve, and the glossopharyngeal nerve supplies the posterior third.

Question 7General and Oral Anatomy, Histology, and Physiology

In the FDI two-digit system, which tooth is designated 36?

  1. Mandibular right first molar
  2. Maxillary right first molar
  3. Maxillary left first molar
  4. Mandibular left first molar Correct answer.

Explanation

In FDI notation the first digit identifies the quadrant and the second the tooth position. Quadrant 3 is the mandibular left, and position 6 is the first molar, so 36 is the mandibular left first molar.

Question 8General and Oral Anatomy, Histology, and Physiology

Which salivary secretion is primarily serous and rich in amylase?

  1. Minor palatal gland secretion
  2. Submandibular gland secretion
  3. Sublingual gland secretion
  4. Parotid gland secretion Correct answer.

Explanation

The parotid gland is a purely serous gland whose secretion is watery and rich in alpha-amylase. The sublingual gland is predominantly mucous, and the submandibular gland is mixed but mainly serous with less amylase than the parotid.

Question 9General and Oral Anatomy, Histology, and Physiology

A patient fractures the mandible at the angle. Which structure is most at risk as it passes near the lingual surface of the body?

  1. Mylohyoid nerve within the pterygomandibular space
  2. Inferior alveolar artery within the mandibular canal
  3. Chorda tympani within the petrotympanic fissure
  4. Lingual nerve in the floor of the mouth Correct answer.

Explanation

The lingual nerve lies close to the lingual cortical plate in the region of the mandibular third molar and is vulnerable during angle or body fractures and related surgery. The inferior alveolar vessels run within the canal, but the lingual nerve's superficial position makes it the classic structure at risk.

Question 10General and Oral Anatomy, Histology, and Physiology

During swallowing, which structure prevents food from entering the nasopharynx?

  1. Soft palate Correct answer.
  2. Epiglottis
  3. Uvula alone
  4. Hyoid bone

Explanation

During the pharyngeal phase of swallowing, the soft palate elevates and tenses to seal the nasopharynx. The epiglottis helps protect the laryngeal inlet, while the hyoid bone serves as a muscular attachment and moves during swallowing.

Question 11General and Oral Anatomy, Histology, and Physiology

Which periodontal fiber group runs from the cementum near the CEJ to the alveolar crest?

  1. Apical fibers
  2. Alveolar crest fibers Correct answer.
  3. Oblique fibers
  4. Horizontal fibers

Explanation

Alveolar crest fibers extend from the cementum just below the cementoenamel junction to the alveolar crest and resist horizontal and intrusive forces. Apical fibers radiate from the root apex, horizontal fibers run at right angles to the long axis, and oblique fibers slant apically to resist axial loading.

Question 12General and Oral Anatomy, Histology, and Physiology

Which primary tooth morphology feature most clearly distinguishes a primary molar from a permanent molar?

  1. Complete lack of enamel
  2. Markedly constricted cervical region with flared crown Correct answer.
  3. Presence of three roots in the mandibular first primary molar
  4. Absence of any pulp chamber

Explanation

Primary molars have a pronounced cervical constriction and a crown that flares toward the occlusal surface, giving a bulbous appearance. They also have thinner enamel and relatively larger pulps, but they do contain pulp chambers, enamel, and typical root patterns.

Question 13General and Oral Anatomy, Histology, and Physiology

A lesion destroys the cell bodies in the trigeminal ganglion. Which function is lost?

  1. Motor supply to the muscles of mastication
  2. Parasympathetic supply to the parotid gland
  3. Taste from the posterior tongue
  4. General sensation from the face and oral cavity Correct answer.

Explanation

The trigeminal ganglion contains the pseudounipolar sensory neurons whose peripheral processes carry general sensation from the face, teeth, and oral cavity. Motor fibers to the masticatory muscles arise from the motor nucleus and exit separately, while taste and parasympathetic fibers travel with other cranial nerves.

Question 14General and Oral Anatomy, Histology, and Physiology

Which statement best describes the arrangement of enamel rods at the dentinoenamel junction?

  1. They are absent, leaving a smooth interface
  2. They are oriented only perpendicular to the long axis of the tooth
  3. They run strictly parallel to the DEJ
  4. They interlock and decussate, increasing resistance to fracture Correct answer.

Explanation

Near the dentinoenamel junction, enamel rods interlock and cross in a decussating pattern that toughens the interface against crack propagation. Rods elsewhere follow a generally perpendicular course from the DEJ toward the surface, so neither strict parallelism nor absence is correct.

Question 15General and Oral Anatomy, Histology, and Physiology

Which factor most directly increases the solubility of enamel apatite in acid?

  1. High fluoride content in the crystal lattice
  2. Increased salivary calcium concentration
  3. Presence of a thick acquired pellicle
  4. High carbonate content in the crystal lattice Correct answer.

Explanation

Carbonate substitution in hydroxyapatite increases crystal strain and acid solubility, making carbonated apatite more vulnerable to demineralization. Fluoride substitution has the opposite effect by stabilizing the lattice and reducing solubility.

Question 16General and Oral Anatomy, Histology, and Physiology

Which nerve fiber type carries sharp, well-localized dental pain most rapidly?

  1. Sympathetic postganglionic fibers
  2. Preganglionic parasympathetic fibers
  3. Unmyelinated C fibers
  4. Thinly myelinated A-delta fibers Correct answer.

Explanation

A-delta fibers are thinly myelinated and conduct impulses rapidly, transmitting the sharp, fast component of dental pain. C fibers are unmyelinated and slower, producing dull aching pain, while autonomic fibers are not involved in transmitting nociceptive dental input.

Question 17General and Oral Anatomy, Histology, and Physiology

Which feature of the temporomandibular joint allows both hinge and gliding movements?

  1. Absence of a joint capsule
  2. Complete bony fusion of the condyle to the temporal bone
  3. A single fibrocartilaginous disc dividing the joint into two compartments Correct answer.
  4. A hyaline cartilage-covered condyle with a single cavity

Explanation

The TMJ is a compound synovial joint in which a fibrocartilaginous articular disc divides the cavity into upper and lower compartments, permitting rotation in the lower and translation in the upper. The condyle is covered by fibrocartilage rather than hyaline cartilage, and the joint has a distinct capsule.

Question 18General and Oral Anatomy, Histology, and Physiology

Which change in saliva most favors caries development?

  1. Increased flow rate after stimulation
  2. Elevated secretory IgA
  3. Increased buffering capacity
  4. Reduced salivary flow with decreased bicarbonate Correct answer.

Explanation

Reduced salivary flow lowers clearance and bicarbonate buffering, allowing plaque pH to fall and remain low after carbohydrate exposure. Increased flow and buffering, along with secretory IgA, generally protect against caries.

Question 19General and Oral Anatomy, Histology, and Physiology

Which epithelial layer of stratified squamous oral mucosa contains cells that are actively dividing?

  1. Stratum spinosum
  2. Stratum basale Correct answer.
  3. Stratum corneum
  4. Stratum granulosum

Explanation

Mitotic activity is concentrated in the stratum basale, where stem and amplifying cells attach to the basement membrane. Cells in the spinous and granular layers are differentiating, and the stratum corneum consists of terminally differentiated cells without mitotic activity.

Question 20General and Oral Anatomy, Histology, and Physiology

Which occlusal relationship describes the mesiobuccal cusp of the maxillary first molar contacting the buccal groove of the mandibular first molar?

  1. Anterior open bite
  2. Class II molar relationship
  3. Class I molar relationship Correct answer.
  4. Class III molar relationship

Explanation

In an Angle Class I molar relationship, the mesiobuccal cusp of the maxillary first molar occludes in the buccal groove of the mandibular first molar. Class II places that cusp mesial to the groove, and Class III places it distal to the groove.

Question 21General and Oral Anatomy, Histology, and Physiology

Which structure separates the submandibular space from the sublingual space?

  1. Medial pterygoid muscle
  2. Buccinator muscle
  3. Mylohyoid muscle Correct answer.
  4. Masseter muscle

Explanation

The mylohyoid muscle forms the muscular floor of the mouth and separates the sublingual space above from the submandibular space below. Infections can spread between these spaces around the posterior free border of the mylohyoid.

Question 22General and Oral Anatomy, Histology, and Physiology

Which tooth surface feature is most characteristic of a maxillary first premolar?

  1. A single conical root with no bifurcation
  2. Three roots in most cases
  3. Two roots in most cases Correct answer.
  4. A rootless crown

Explanation

The maxillary first premolar usually has two roots, one buccal and one palatal, which is a key identifying feature. The maxillary second premolar typically has a single root, and no premolar is normally rootless.

Question 23General and Oral Anatomy, Histology, and Physiology

A patient has lost the ability to protrude the mandible on one side after a nerve injury. Which muscle is most likely affected?

  1. Lateral pterygoid Correct answer.
  2. Masseter
  3. Medial pterygoid
  4. Temporalis

Explanation

The lateral pterygoid is the principal protrusor of the mandible, assisted by the digastric and geniohyoid. The temporalis, masseter, and medial pterygoid are primarily elevators, so their loss would impair closure rather than protrusion.

Question 24General and Oral Anatomy, Histology, and Physiology

Which histological change best explains the increased permeability of inflamed junctional epithelium?

  1. Thickening of the keratin layer
  2. Widening of intercellular spaces with reduced hemidesmosomes Correct answer.
  3. Deposition of acellular cementum
  4. Increase in the number of desmosomes

Explanation

In gingival inflammation, junctional epithelium shows widened intercellular spaces, fewer hemidesmosomes, and vacuolization, allowing bacterial products and inflammatory cells to pass more readily. Keratinization and desmosome density do not increase in this region, and cementum deposition is unrelated to epithelial permeability.

Question 25General and Oral Anatomy, Histology, and Physiology

Which mechanism best explains why a carious lesion in enamel appears as a white spot before cavitation?

  1. Subsurface demineralization with a relatively intact surface layer Correct answer.
  2. Deposition of reparative dentin at the DEJ
  3. Bacterial invasion of the dentinal tubules
  4. Complete dissolution of the entire enamel thickness

Explanation

Early enamel caries involves subsurface loss of mineral while the surface layer remains relatively mineralized and porous, scattering light and appearing chalky white. The lesion has not yet cavitated, and dentinal changes occur only after the process advances to the DEJ.

Question 26General and Oral Anatomy, Histology, and Physiology

Which type of oral epithelium lines the buccal mucosa and the ventral surface of the tongue?

  1. Nonkeratinized stratified squamous epithelium Correct answer.
  2. Parakeratinized stratified squamous epithelium
  3. Keratinized stratified squamous epithelium
  4. Pseudostratified ciliated columnar epithelium

Explanation

Lining mucosa covers flexible, non–load-bearing regions such as the buccal mucosa, ventral tongue, and soft palate, and is protected by a nonkeratinized stratified squamous epithelium. Keratinization is a specialization for regions exposed to masticatory friction, so it is not the pattern of these flexible surfaces.

Question 27General and Oral Anatomy, Histology, and Physiology

Which component of whole saliva is the principal calcium-binding phosphoprotein that maintains supersaturation with respect to enamel mineral?

  1. Proline-rich proteins
  2. Secretory IgA
  3. Lysozyme
  4. Statherin Correct answer.

Explanation

Statherin is a tyrosine-rich phosphoprotein that binds calcium and inhibits precipitation of calcium phosphate, keeping saliva supersaturated so that enamel demineralization is limited. Proline-rich proteins also bind calcium but are best known for binding tannins and hydroxyapatite, whereas secretory IgA and lysozyme serve immune and antibacterial roles.

Question 28General and Oral Anatomy, Histology, and Physiology

A mandibular first molar is viewed from the occlusal aspect. Which groove pattern most commonly describes its arrangement of cusps and developmental grooves?

  1. A straight buccolingual groove separating two cusps
  2. A T-shaped pattern formed by the central and lingual grooves
  3. A cross-shaped pattern with four cusps of equal size
  4. A Y-shaped pattern with the distobuccal groove meeting the lingual groove Correct answer.

Explanation

The mandibular first molar typically has five cusps and a Y-shaped occlusal groove pattern in which the distobuccal groove joins the lingual developmental groove. This differs from the mandibular second molar, which more often shows a cross-shaped pattern with four cusps.

Question 29General and Oral Anatomy, Histology, and Physiology

Which change in the ionic composition of plaque fluid most directly promotes enamel demineralization beneath a mature plaque biofilm?

  1. A rise in pH above 7.0 after carbohydrate clearance
  2. An increase in salivary flow rate during chewing
  3. A fall in pH to about 5.5 or below after sugar fermentation Correct answer.
  4. An increase in fluoride concentration within plaque fluid

Explanation

When plaque bacteria ferment sugars, organic acids accumulate and plaque fluid pH falls to the critical level near 5.5, at which enamel hydroxyapatite dissolves faster than it reprecipitates. This net loss of mineral produces the subsurface demineralization characteristic of caries.

Question 30General and Oral Anatomy, Histology, and Physiology

A patient sustains a lesion of the motor fibers of the facial nerve just after they exit the stylomastoid foramen. Which functional deficit is most consistent with this level of injury?

  1. Loss of taste from the anterior two-thirds of the tongue
  2. Reduced salivary flow from the parotid gland on the affected side
  3. Inability to close the ipsilateral eye and raise the corner of the mouth Correct answer.
  4. Loss of general sensation from the anterior two-thirds of the tongue

Explanation

Fibers leaving the stylomastoid foramen are the branchial motor fibers to the muscles of facial expression, so a lesion at this point produces ipsilateral facial weakness such as incomplete eye closure. Taste to the anterior tongue and secretomotor supply to the parotid travel with the chorda tympani, which branches off higher in the facial canal and would be spared.

Question 31Head and Neck Anatomy

Which cranial nerve provides motor innervation to the intrinsic muscles of the tongue, with the exception of the palatoglossus?

  1. Vagus nerve (CN X)
  2. Hypoglossal nerve (CN XII) Correct answer.
  3. Mandibular division of the trigeminal nerve (CN V3)
  4. Glossopharyngeal nerve (CN IX)

Explanation

The hypoglossal nerve (CN XII) is the motor supply to all intrinsic and most extrinsic tongue muscles, including genioglossus, hyoglossus, and styloglossus. The single exception is palatoglossus, which is supplied by the pharyngeal plexus via the vagus. Injury to CN XII produces tongue deviation toward the side of the lesion on protrusion.

Question 32Head and Neck Anatomy

Sensation from the anterior two-thirds of the tongue for taste is carried by which nerve?

  1. Greater petrosal branch of the facial nerve
  2. Lingual branch of the glossopharyngeal nerve
  3. Mylohyoid branch of the inferior alveolar nerve
  4. Chorda tympani branch of the facial nerve Correct answer.

Explanation

Taste from the anterior two-thirds of the tongue travels via the chorda tympani, a branch of the facial nerve (CN VII), which joins the lingual nerve in the infratemporal fossa. General sensation from the same region is carried by the lingual nerve (V3), but taste fibers are facial. The posterior third carries taste through CN IX.

Question 33Head and Neck Anatomy

The parotid duct (Stensen duct) opens into the oral cavity at which location?

  1. The floor of the mouth beside the frenulum of the tongue
  2. The lesser palatine foramen
  3. The sublingual fold along the tongue margin
  4. The papilla in the cheek opposite the maxillary second molar Correct answer.

Explanation

The parotid duct crosses the masseter, turns medially at its anterior border, pierces the buccinator, and opens at a papilla in the buccal mucosa opposite the crown of the maxillary second molar. This landmark is used clinically when cannulating the duct or diagnosing parotid obstruction. The submandibular duct opens at the sublingual caruncle instead.

Question 34Head and Neck Anatomy

Which structure passes through the foramen ovale?

  1. Internal carotid artery
  2. Mandibular division of the trigeminal nerve (V3) Correct answer.
  3. Middle meningeal artery
  4. Maxillary division of the trigeminal nerve (V2)

Explanation

The foramen ovale in the greater wing of the sphenoid transmits the mandibular division of the trigeminal nerve (V3) along with the lesser petrosal nerve and accessory meningeal artery. It is a key landmark because V3 supplies the muscles of mastication and the lower face. The maxillary division instead exits through the foramen rotundum.

Question 35Head and Neck Anatomy

The temporomandibular joint is best described as which type of articulation?

  1. A fibrous synarthrosis between the temporal and mandibular bones
  2. A synovial joint with an articular disc that permits both rotation and translation Correct answer.
  3. A pure hinge (ginglymus) joint
  4. A cartilaginous symphysis

Explanation

The temporomandibular joint is a synovial, bicondylar joint divided into two compartments by a fibrocartilaginous articular disc. The lower compartment permits rotation, while the upper compartment permits translation as the condyle slides onto the articular eminence during opening. This combination makes it a hinge-and-sliding joint rather than a simple hinge.

Question 36Head and Neck Anatomy

A patient cannot elevate the corner of the mouth on the right side and has flattening of the right nasolabial fold. Which muscle is most directly responsible for the lost lip elevation?

  1. Masseter
  2. Zygomaticus major Correct answer.
  3. Buccinator
  4. Levator veli palatini

Explanation

Zygomaticus major runs from the zygomatic bone to the angle of the mouth and elevates the corner of the mouth during smiling. Loss of this action with nasolabial flattening suggests facial nerve weakness. Buccinator compresses the cheek against the teeth and does not elevate the oral commissure.

Question 37Head and Neck Anatomy

During surgery in the posterior triangle of the neck, injury to the spinal accessory nerve (CN XI) would most likely produce which deficit?

  1. Loss of sensation over the chin
  2. Weakness in shrugging the shoulder and rotating the head Correct answer.
  3. Deviation of the uvula to the opposite side
  4. Inability to protrude the tongue

Explanation

The spinal accessory nerve supplies the sternocleidomastoid and trapezius, so injury causes weakness in shoulder elevation (shrugging) and head rotation against resistance. The nerve is superficial in the posterior triangle, making it vulnerable during lymph node biopsy. Tongue protrusion and palatal movement are mediated by other cranial nerves.

Question 38Head and Neck Anatomy

Lingual nerve damage during third molar extraction would most likely cause which finding?

  1. Loss of taste over the posterior third of the tongue
  2. Loss of sensation over the lower lip and chin
  3. Numbness of the anterior two-thirds of the tongue and loss of taste in that region Correct answer.
  4. Paralysis of the intrinsic tongue muscles

Explanation

The lingual nerve carries general sensation from the anterior two-thirds of the tongue and, before it separates, taste fibers of the chorda tympani. Injury therefore produces numbness and taste loss in that region. The inferior alveolar nerve, not the lingual nerve, supplies the lower lip and chin.

Question 39Head and Neck Anatomy

Which muscle of mastication is the primary depressor of the mandible during opening?

  1. Lateral pterygoid Correct answer.
  2. Temporalis
  3. Medial pterygoid
  4. Masseter

Explanation

The lateral pterygoid pulls the condyle and disc forward onto the articular eminence, initiating mandibular depression and protrusion. The other three muscles of mastication (masseter, temporalis, medial pterygoid) primarily elevate the mandible. The digastric and mylohyoid assist in opening but are suprahyoid muscles rather than classic muscles of mastication.

Question 40Head and Neck Anatomy

The pterion is a clinically important landmark because it overlies which vessel?

  1. Occipital artery
  2. Superficial temporal artery
  3. Facial artery
  4. Middle meningeal artery Correct answer.

Explanation

The pterion is the junction of the frontal, parietal, temporal, and sphenoid bones at the anterolateral skull. It is thin and overlies the anterior branch of the middle meningeal artery, so trauma here can cause an epidural hematoma. The superficial temporal and occipital arteries run outside the skull.

Question 41Head and Neck Anatomy

A lesion of the chorda tympani proximal to its junction with the lingual nerve would produce which combination?

  1. Loss of general sensation on the anterior tongue with preserved taste
  2. Loss of taste on the posterior tongue only
  3. Loss of taste on the anterior tongue with preserved general sensation Correct answer.
  4. Loss of both taste and general sensation on the anterior tongue

Explanation

The chorda tympani carries only special sensory (taste) and parasympathetic fibers, while general sensation of the anterior tongue travels in the lingual nerve proper. A lesion confined to the chorda tympani therefore abolishes taste but leaves touch and pain intact. Combined loss of both modalities would require lingual nerve injury.

Question 42Head and Neck Anatomy

Which paranasal sinus drains into the middle meatus of the nasal cavity?

  1. Maxillary sinus Correct answer.
  2. Nasolacrimal duct
  3. Sphenoid sinus
  4. Posterior ethmoid air cells

Explanation

The maxillary sinus drains through its ostium into the hiatus semilunaris of the middle meatus, along with the frontal sinus and anterior ethmoid cells. This shared drainage pathway explains why maxillary sinusitis often coexists with frontal and ethmoid disease. The sphenoid and posterior ethmoid cells drain into the superior meatus.

Question 43Head and Neck Anatomy

The greater palatine foramen transmits which structures?

  1. The greater palatine nerve and vessels Correct answer.
  2. The maxillary division of the trigeminal nerve
  3. The nasopalatine nerve
  4. The lesser palatine nerve only

Explanation

The greater palatine foramen, located in the posterolateral hard palate, transmits the greater palatine nerve and descending palatine vessels to supply the hard palate and palatal gingiva. The nasopalatine nerve instead passes through the incisive canal. The lesser palatine nerve exits via the lesser palatine foramen.

Question 44Head and Neck Anatomy

A patient reports numbness of the lower lip and chin after a mandibular fracture involving the mandibular canal. Which nerve has been compromised?

  1. Inferior alveolar nerve Correct answer.
  2. Buccal nerve
  3. Mylohyoid nerve
  4. Auriculotemporal nerve

Explanation

The inferior alveolar nerve runs within the mandibular canal and gives off the mental nerve, which supplies sensation to the lower lip and chin. A fracture crossing the canal can stretch or lacerate the nerve, producing numbness in that distribution. The buccal and auriculotemporal nerves supply other regions of the face and scalp.

Question 45Head and Neck Anatomy

In a patient with a unilateral lesion of the recurrent laryngeal nerve, which finding is expected?

  1. The vocal fold on the affected side lies in a paramedian position with hoarseness Correct answer.
  2. The tongue deviates toward the affected side
  3. The uvula deviates toward the affected side
  4. The soft palate deviates away from the affected side

Explanation

The recurrent laryngeal nerve supplies all intrinsic laryngeal muscles except the cricothyroid, so unilateral injury leaves the affected vocal fold immobile, often in a paramedian position, causing hoarseness. On the left side the nerve loops under the aortic arch, making it vulnerable to mediastinal disease. Tongue and palatal deviation reflect hypoglossal and vagal pharyngeal branch lesions, respectively.

Question 46Head and Neck Anatomy

Which statement best explains why the submandibular gland is more prone to ductal obstruction than the parotid gland?

  1. Its duct opens at a papilla on the buccal mucosa opposite the second molar
  2. Its duct ascends against gravity and opens at the sublingual caruncle, favoring stasis and calculus formation Correct answer.
  3. It receives parasympathetic supply from the glossopharyngeal nerve
  4. It lacks a capsule and is therefore freely mobile

Explanation

Wharton duct runs upward and forward to open at the sublingual caruncle, so saliva must travel against gravity and the duct has a narrow, tortuous course. This anatomy predisposes to stasis and sialolith formation, which are far more common in the submandibular gland. The parotid duct is longer but runs a more direct horizontal course.

Question 47Oral Pathology and Oral Medicine

A 28-year-old patient presents with a painless, fluctuant swelling of the lower lip that has been present for several weeks and occasionally ruptures and drains. Histologically the lesion shows a cystic cavity lined by granulation tissue with numerous foamy macrophages. Which diagnosis is most likely?

  1. Hemangioma
  2. Pleomorphic adenoma
  3. Fibroma
  4. Mucocele (extravasation phenomenon) Correct answer.

Explanation

Lower lip swellings that rupture and drain are classically mucoceles, caused by extravasation of saliva from a severed minor salivary gland duct. The granulation-tissue lining with foamy macrophages engulfing mucin is the characteristic histologic picture. Hemangiomas blanch on pressure and are vascular, while fibromas and pleomorphic adenomas do not show this mucin-driven granulation lining.

Question 48Oral Pathology and Oral Medicine

Which organism is the principal etiologic agent of acute necrotizing ulcerative gingivitis (ANUG)?

  1. Actinomyces israelii
  2. Streptococcus mutans
  3. Candida albicans
  4. Prevotella intermedia Correct answer.

Explanation

ANUG is a fusospirochetal infection in which Prevotella intermedia is a key cultivable organism, acting together with fusiform bacilli and spirochetes. The clinical picture includes punched-out, crater-like papillae, pseudomembrane, and fetor oris. Streptococcus mutans drives caries, Candida causes candidiasis, and Actinomyces causes actinomycosis.

Question 49Oral Pathology and Oral Medicine

A patient has recurrent crops of small vesicles on the vermilion border of the lip that crust and heal within about ten days. Which diagnosis best fits this presentation?

  1. Herpes labialis Correct answer.
  2. Oral lichen planus
  3. Aphthous major ulcer
  4. Secondary syphilis

Explanation

Recurrent grouped vesicles on the lip vermilion that crust and heal in 7 to 10 days represent herpes labialis, usually due to reactivation of herpes simplex virus type 1. The prodrome of tingling and the recurrent pattern at the same site are characteristic. Aphthous ulcers are intraoral and not vesicular, syphilis produces a painless chancre or mucous patches, and lichen planus shows white striae.

Question 50Oral Pathology and Oral Medicine

Which radiographic or clinical feature is most characteristic of an ameloblastoma of the posterior mandible?

  1. A unilocular radiolucency at the apex of a nonvital tooth
  2. A well-defined multilocular radiolucency with a soap-bubble appearance Correct answer.
  3. A diffuse ground-glass opacity of the jaw
  4. A sunburst periosteal reaction with a Codman triangle

Explanation

Ameloblastoma classically appears as a well-defined, multilocular radiolucency described as soap-bubble or honeycomb, most often in the posterior mandible. It is locally aggressive and expansile despite being benign. Ground-glass opacity suggests fibrous dysplasia, sunburst periosteal reaction suggests osteosarcoma, and a periapical radiolucency on a nonvital tooth suggests a radicular cyst.