Destruction of which component of the skin leads to hypopigmentation in burn patients?

Correct Answer: B

Rationale: The correct answer is B: Melanocytes. Melanocytes are responsible for producing melanin, the pigment that gives skin its color. In burn patients, destruction of melanocytes leads to hypopigmentation as there is a reduced or absence of melanin production. Keratinocytes (A) are the most abundant cells in the epidermis, but they do not contribute to skin pigmentation. Basement membrane (C) provides structural support but does not play a direct role in skin pigmentation. Hair follicles (D) are primarily involved in hair growth and do not affect skin pigmentation directly.

Correct Answer: C

Rationale: The correct answer is C: Arterial insufficiency. Cold therapy constricts blood vessels, which can worsen arterial insufficiency by further reducing blood flow. Acute sprains, chronic muscle spasms, and spasticity benefit from cold therapy due to its ability to reduce inflammation, pain, and muscle spasm respectively. Cold therapy is contraindicated for arterial insufficiency as it can exacerbate the condition by further compromising blood flow.

Correct Answer: B

Rationale: The correct answer is B: Dorsal surface of the hand; the skin is thinner on this surface than on the palms. Rationale: 1. The dorsal surface of the hand has thinner skin compared to the thicker skin on the palmar surface, making it more sensitive to temperature changes. 2. Thinner skin allows for better detection of subtle temperature variations, making it ideal for accurately assessing the patient's skin temperature. 3. The fingertips (choice A) may be more sensitive to touch, but for temperature assessment, the dorsal surface is more reliable due to its thinner skin. 4. The ulnar portion of the hand (choice C) having increased blood supply does not necessarily enhance temperature sensitivity; it is more related to vascular function. 5. The palmar surface (choice D) may have increased nerve supply, but its thickness can dampen the sensitivity to detect subtle temperature changes. In summary, the correct choice (B) is supported by the anatomical characteristics of the dorsal hand

Correct Answer: B

Rationale: The correct answer is B: Optic nerve damage on the left. When both pupils dilate slightly but the right pupil constricts briskly when light is shone on it, it indicates an afferent defect in the left eye. The optic nerve carries afferent (sensory) signals from the eye to the brain. Since the left optic nerve is damaged, the afferent signal from the left eye is not transmitted properly, resulting in the dilated pupils. The brisk constriction of the right pupil in response to light indicates that the efferent (motor) pathway is intact on the right side. Therefore, the problem is likely on the afferent pathway of the left optic nerve. Incorrect choices: A: Optic nerve damage on the right - Incorrect because the brisk constriction of the right pupil indicates the efferent pathway on the right is intact. C: Efferent nerve damage on the right - Incorrect because the brisk constriction of the

Correct Answer: C

Rationale: The correct answer is C: Ankle–brachial index (ABI). ABI is a non-invasive test used to assess peripheral vascular disease by comparing blood pressure in the ankle with blood pressure in the arm. In this case, the patient's risk factors (smoking, hypertension) make him susceptible to PVD. Venogram (A) involves injecting contrast dye into a vein to visualize blood flow, which is invasive and not typically used as an initial test. CT scan (B) is useful for imaging but not specific for PVD evaluation. PET scan (D) is used for detecting metabolic activity and is not a standard test for PVD. Therefore, C is the most appropriate initial test for evaluating PVD in this patient.