Matching: Proximal weakness

Correct Answer: B

Rationale: Myopathies (e.g., muscular dystrophy) typically present with proximal weakness. Polyneuropathy causes distal weakness; neuromuscular junction defects and upper motor neuron defects don't specifically target proximal muscles.

Correct Answer: C

Rationale: Duchenne muscular dystrophy presents with proximal weakness (difficulty climbing stairs), delayed motor milestones, and pseudohypertrophy of calves. Other conditions don't match this pattern.

Correct Answer: B

Rationale: Malignant hyperthermia is triggered by anesthetics (e.g., halothane), not radiographic dyes, making B false. It's autosomal dominant, causes myoglobinuria, and is treated with dantrolene.

Correct Answer: A

Rationale: Anti-acetylcholine receptor antibodies are highly specific and the best diagnostic tool for myasthenia gravis.

Correct Answer: C

Rationale: At birth, ossification centers for the distal femur, proximal tibia, and calcaneus are typically present, but the distal humerus ossification center appears later, usually between 6 months and 1 year.