The nerve that is injured during a mastectomy, sometimes leading to postmastectomy pain syndrome, is which of the following?

Correct Answer: A

Rationale: The correct answer is A: Intercostobrachial nerve. During a mastectomy, the intercostobrachial nerve is often damaged, leading to postmastectomy pain syndrome. This nerve runs along the chest and upper arm, making it susceptible to injury during the surgery. The suprascapular nerve (B) innervates the shoulder joint, the musculocutaneous nerve (C) innervates the muscles of the anterior arm, and the axillary nerve (D) innervates the deltoid and teres minor muscles, none of which are directly affected during a mastectomy. Thus, these choices are incorrect.

Correct Answer: A

Rationale: The correct answer is A: Marked wrist and finger drop. In Saturday night palsy, there is compression of the radial nerve, leading to weakness of the wrist and finger extensors. This results in the characteristic presentation of wrist and finger drop. Choice B is incorrect as atrophy of the APB is seen in carpal tunnel syndrome. Choice C is incorrect as weak elbow extension is not a typical finding in Saturday night palsy. Choice D is incorrect as painless weakness and atrophy of hand intrinsic muscles are more indicative of ulnar nerve compression.

Correct Answer: D

Rationale: The correct answer is D because diplopia with one eye covered suggests a problem with the affected eye itself, such as an irregularity in the cornea or lens causing refractive errors. Weakness of CN III (A) would cause eye movement issues, not diplopia with one eye covered. Weakness of CN IV (B) would result in vertical diplopia, not diplopia with one eye covered. A lesion of the brainstem (C) can lead to various oculomotor issues but wouldn't specifically cause diplopia with one eye covered.

Correct Answer: C

Rationale: The correct answer is C: Ureteral stone. The progression of pain from under the lower ribs to the lateral abdomen and then to the right lower quadrant is characteristic of a ureteral stone passing from the kidney towards the bladder. This pattern is known as "Loin to groin pain." Appendicitis typically presents with pain starting in the right lower quadrant without a gradual progression. Dysmenorrhea involves cramping pelvic pain related to menstruation. Ovarian cyst pain is usually localized to the lower abdomen and may not follow the described pattern.

Correct Answer: C

Rationale: The correct answer is C: Calf. Atherosclerosis in the lower extremities typically presents as intermittent claudication, which is characterized by pain, cramping, or fatigue in the calf muscles during physical activity. This occurs due to insufficient blood flow to the muscles affected by the narrowed arteries. Pain in the thigh (A), knee (B), or ankle (D) would not be as specific for atherosclerosis in the lower extremities, as the calf is the most common site for this condition.