MCQs

Universal precautions apply to every patient as if potentially infectious HIV status is irrelevant to the infection control protocol ADA Code of Ethics (1988): Refusing dental treatment solely because a patient is HIV-positive or refuses HIV testing is both unethical and illegal Patient has the legal right to refuse HIV-related testing; requiring it as a precondition violates patlent autonomy Treat normally with strict infection control (gloves, mask, eye protection, sterilisation of instruments) - this is the legally and ethically correct approach

Airborne is the most difficult to control - droplet nuclei (< 5 um) remain suspended in air for prolonged periods, travel long distances, and require specialized engineering controls negative pressure rooms, HEPA filters, N95 respirators) that are difficult to scale * Other routes have targetable interruption points: vector-borne → kill the vector; vertical → screen and treat the mother, human-to-human → isolate, vaccinate, barrier precautions * High Roof airborne diseases (Measles Ro = 12-18; TB) reflects the inherent difficulty of containment * Examples of airborne pathogens: M. tuberculosis, Measles virus, Varicella-zoster virus smallpox

Point prevalence - all existing cases (old + new) at a single point in time * "February 15th" is a specific calendar date → one frozen moment → point, not a period * Distinguishing feature vs. period prevalence: period prevalence spans a duration (e.g., a week or month):

Incidence = new cases occurring in a population at risk during a specified time. Prevalence = all existing cases (old + new). Incidence is useful for studying risk of developing disease.

* Hypoglossal canal = anterior condylar canal - located in the occipital bone, opening internally into the posterior cranial fossa * Transmits: CN XII (hypoglossal nerve) + meningeal branch of ascending pharyngeal artery + meningeal branch of CN XII (C1 fibres) + emissary vein (sigmold sinus → IJV) * All three statements (A, B, C) are correct → D (All of the above) * The meningeal branch of the ascending pharyngeal artery is the most commonly missed content in exam preparation

Asterion = junction of parietomastoid + occipitomastoid + lamboid. sutures → meeting of parietal, occipital, and mastold (temporal) bones * Located posterolaterally on the skull * Overlies the transverse-sigmoid sinus junction - key surgical landmark for posterlor fossa/retrosigmoid approaches * Most common site of Wormian bones (along with lambda) * Not to be confused with pterion frontal + parietal + sphenoid + squamous temporal; overlles middle meningeal artery

The facial skelston has 14 bones :6 paired (12 bones )+2 unpaired (vomer+mandible).Vomer is single midline bone forming the posteroinferior nasal septum -one of two unpaired facial bones

Because the natural ostium is located near the roof of the maxillary sinus, fluid cannot drain by gravity when the head is upright. Drainage relies completely on the coordinated action of the ciliary epithelium moving mucus upward and outward toward the opening.

The lingula is a tongue-like bony projection overlapping the mandibular foramen anteriorly, and its apex and posterior margin serve as the attachment site for the sphenomandibular ligament (a derivative of Meckel's cartilage).