A young athlete develops heel pain with activity that decreases with rest; he is limping with no swelling. He has pain to palpation of the posterior calcaneus and tight heel cords. Infection and tumor were excluded by radiographs. Of the following, the MOST likely diagnosis is

Correct Answer: B

Rationale: Sever disease (calcaneal apophysitis) is common in young athletes with heel pain from growth plate stress.

Correct Answer: D

Rationale: Spasticity is a hallmark of upper motor neuron defects (e.g., stroke), due to increased muscle tone. Polyneuropathy, myopathy, and neuromuscular junction defects don't cause spasticity.

Correct Answer: D

Rationale: All statements are true: CK reflects muscle damage, MM is in skeletal muscle, MB in cardiac muscle, and BB in brain (not smooth muscle), but the question asks for the false statement, and all are correct as phrased, making this tricky. Assuming intent, D is least accurate in context.

Correct Answer: C

Rationale: Weakness of respiratory muscles is common in myasthenia gravis, especially in crisis, unlike the other options.

Correct Answer: D

Rationale: Macrodactyly, or localized gigantism, is associated with Proteus syndrome, Neurofibromatosis, and Tuberous sclerosis, but Alport syndrome primarily affects the kidneys and hearing, not limb overgrowth.