Correct Answer: A

Rationale: Inspiratory splitting of S occurs due to the normal physiological delay in the closure of the aortic and pulmonic valves during inspiration. During inspiration, the negative intrathoracic pressure leads to increased venous return to the right side of the heart, causing a slight delay in the closure of the pulmonic valve. This results in the aortic valve closing first, followed by the closure of the pulmonic valve, leading to the splitting of S during inspiration.

Correct Answer: C

Rationale: The young violinist is experiencing symptoms of anxiety specifically related to performing in front of others, which is characteristic of social phobia (also known as social anxiety disorder). The symptoms occur only during performances, indicating the anxiety is triggered by social situations where he is the center of attention. His ability to perform without symptoms during rehearsals or practice sessions further supports the diagnosis of social phobia, as the anxiety is specifically related to public performance. In contrast, panic disorder is characterized by recurrent, unexpected panic attacks that are not situation-specific, and specific phobia involves an intense fear of a specific object or situation, neither of which fully match this patient's presentation. Generalized anxiety disorder involves excessive worry and anxiety about various aspects of life, which is not the main feature of this case.

Correct Answer: C

Rationale: The most likely explanation for Mrs. Lenzo noticing a 4-pound weight gain over just 2 days is fluctuations in body fluid. Our body weight can fluctuate throughout the day due to factors such as hydration levels, sodium intake, and hormonal changes. It is not physically possible to gain 4 pounds of actual body mass (e.g., fat or muscle) in such a short period of time by overeating or wearing different clothing. Additionally, if Mrs. Lenzo's scale is very accurate as mentioned, it is less likely that the weight gain is due to instrument inaccuracy. Therefore, the most plausible reason for the sudden weight gain is fluctuations in body fluid retention.

Correct Answer: D

Rationale: All of the mentioned techniques are important in performing a rectal examination.

Correct Answer: D

Rationale: Chronic arterial insufficiency results in poor blood flow to the lower extremities. This leads to inadequate oxygen and nutrient supply to the tissues, causing damage and changes in the skin. A common physical examination finding in chronic arterial insufficiency is thin, shiny, atrophic skin. The skin may appear pale, cool to the touch, and may have decreased hair growth. It is important to note that other findings such as diminished or absent pulses and reduced temperatures may also be present with chronic arterial insufficiency.