Hair-on-end appearance in a skull roentgenogram is seen in:

 # " Hair-on-end" appearance in a skull roentgenogram is seen in:

a. Fibrous dysplasia 

b. Thalassemia 

c. Garre's Osteomyelitis 

d. Paget's Disease 

The correct answer is B. Thalassemia.

Similar to sickle cell anemia, the features of thalassemia generally result from hyperplasia of the ineffective bone marrow and its subsequent failure to produce normal red blood cells. However, these changes are usually more severe than with other anemias. There is a generalized radiolucency of the long bones with cortical thinning. In the skull, the diploic space exhibits marked thickening, especially in the frontal region. The skull also shows a generalized granular appearance, and occasionally a “hair-on-end” effect may develop.

Vesicles rupture at followed by pseudo membrane formation on a 3 year old child

 # A 3 year old patient has extensive vesicles on lip, tongue, oral mucous membrane. After 2-4 days vesicles rupture at followed by pseudo membrane formation and also some dermal lesions are seen. What will be the diagnosis? 

a. Herpetic stomatitis 

b. Erythema multiforme 

c. ANUG 

d. Steven-Johnson Syndrome 

The correct answer is B. Erythema multiforme. 

Erythema multiforme (EM) is acute, self‐limited, inflammatory mucocutaneous disease that manifests on the skin and often oral mucosa, although other mucosal surfaces, such as the genitalia, may also be involved. It represents a hypersensitivity reaction to infectious agents (majority of cases) or medications. In general, EM is classified as EM minor if there is less than 10% of skin involvement and there is minimal to no mucous membrane involvement, whereas EM major has more extensive but still characteristic skin involvement, with the oral mucosa and other mucous membranes affected.

Three inherent characteristics of a radiographic film:

 # Three inherent characteristics of a radiographic film:

a. density, distortion, contrast 

b. sharpness, contrast, density 

c. definition, sharpness, penumbra 

d. distortion, detail, sharpness 

The correct answer is: B. Sharpness, contrast, density.

Image quality describes the subjective judgment by the clinician of the overall appearance of a radiograph. It combines the features of density, contrast, latitude, sharpness, resolution, and perhaps other parameters.

Use of intensifying screen is:

 # Use of intensifying screen is:

a. to decrease scattered radiation 

b. to decrease patient radiation 

c. to increase contrast 

d. to increase number of photons striking the anode filament 

The correct answer is B. To decrease patient radiation.

The presence of intensifying screens creates an image receptor system that is 10 to 60 times more sensitive to x-rays than the film alone. Consequently, the use of intensifying screens substantially reduces the dose of x radiation to the patient. Intensifying screens are used with films for virtually all extraoral radiography, including panoramic, cephalometric, and skull projections.