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16 multiple-choice questions and 3 flashcards on Musculoskeletal, Skin & Subcutaneous Tissue, about 9% of the USMLE Step 1 bank. Every one carries a written rationale.
Musculoskeletal, Skin & Subcutaneous Tissue is one of 10 chapters in CoStudy's USMLE Step 1 — Medical Licensing bank, and it holds 16 of the bank's 172 multiple-choice questions — roughly 9% of the total. That proportion is not arbitrary: chapters follow the certifying body's published exam outline, and the number of questions in each is set by that domain's published weight, so the share of your practice time this chapter takes matches the share of the real exam it accounts for.
Studying by chapter is worth doing once you have a diagnostic score. A single overall percentage tells you whether you are close; it does not tell you which domain is dragging. Working a weak chapter in isolation, and re-testing it in isolation, is the fastest way to move a score that has stalled — and it is why the mock exams in CoStudy report by domain rather than as one number.
2 questions drawn from this chapter, with the full rationale shown — the controlling principle behind the right answer, and why each wrong option tempts and fails.
Which muscle fiber type is fatigue-resistant, has high mitochondrial content, and relies primarily on oxidative metabolism?
Answer: A — Type I (slow oxidative)
Type I fibers are slow-twitch, red (myoglobin-rich), packed with mitochondria, fatigue-resistant — adapted for endurance. Type IIx/IIb fibers are fast-twitch, white, glycolytic, and fatigue rapidly — adapted for short, explosive efforts.
A 60-year-old man with chronic sun exposure has a slowly enlarging pearly papule with telangiectasias and a central depression on his nose. Biopsy shows nests of basaloid cells with peripheral palisading. Which is the MOST important behavior of this lesion?
Answer: A — Locally invasive; rare metastasis
A) Correct: basal cell carcinoma is locally invasive but rarely metastasizes (<0.1%); aggressive treatment of the local lesion prevents disfigurement. B) BCC rarely metastasizes to nodes — overestimates aggression. C) Hematogenous spread is exceedingly rare. D) Perineural invasion can occur in aggressive variants but isn't the primary pattern. E) BCC does NOT spontaneously regress (unlike keratoacanthoma) — common misconception.
1 cards from the 3 in this chapter.
Melanoma ABCDE?
Asymmetry, Border irregular, Color variation, Diameter >6mm, Evolving.
These are a sample. The full Musculoskeletal, Skin & Subcutaneous Tissue chapter runs 19 items with per-chapter progress tracking, on the web and in the iOS app.
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