TL;DR. The MRCEM Primary blueprint is 180 single-best-answer questions split: Anatomy 60 (33.3%), Physiology 60 (33.3%), Pharmacology 24 (13.3%), Microbiology 17 (9.4%), Evidence-Based Medicine 10 (5.6%), Pathology 9 (5%). Two-thirds of your marks live in anatomy and physiology. If you treat them as equally weighted with pharmacology you will run out of time and fail. Allocate revision hours in roughly the same proportion as the marks — and inside anatomy, prioritise upper limb, lower limb and head & neck because that is where most questions sit.
You are likely reading this at the point most candidates hit — six to eight weeks out, anatomy is eating your evenings, and you are starting to wonder whether all of it actually appears on the paper. Short version: yes, a lot of it does, and you cannot dodge it. But the blueprint is more lopsided than people realise, and once you map your hours onto the actual mark split the workload becomes survivable.
What is the official MRCEM Primary blueprint?
The MRCEM Primary is a 3-hour, 180-question single-best-answer paper delivered through Pearson VUE. RCEM publishes the exact category split in the MRCEM Primary Regulations and Information Pack. The blueprint has been stable since the August 2021 switch from FRCEM Primary to MRCEM Primary, and the content map itself goes back to the RCEM Basic Sciences Curriculum (June 2010) — see why the MRCEM Primary 2010 syllabus is still current.
The six-domain split (verified May 2026)
| Domain | Questions | % of paper | Sub-topics in scope |
|---|---|---|---|
| Anatomy | 60 | 33.3% | Upper limb, lower limb, thorax, abdomen, head & neck, central nervous system, cranial nerve lesions |
| Physiology | 60 | 33.3% | Basic cellular, respiratory, cardiovascular, gastrointestinal, renal, endocrine |
| Pharmacology | 24 | 13.3% | GI, CV, respiratory, CNS, infections, endocrine, fluids & electrolytes, MSK, immunology & vaccines, anaesthesia |
| Microbiology | 17 | 9.4% | Principles of microbiology, pathogen groups |
| Evidence-Based Medicine | 10 | 5.6% | Statistics, study methodology, principles of critical appraisal |
| Pathology | 9 | 5% | Inflammatory responses, immune responses, infection, wound healing, haematology |
| Total | 180 | 100% | 3 hours, 1 minute per question |
You will see this split summarised online as “40% anatomy / 40% physiology” — that is a rounding error people repeat on Reddit. The exact figure is 33.3% each. Together they still deliver two-thirds of your marks, so the heuristic is correct even if the percentages aren’t.
How much anatomy do I actually need to learn?
Enough to confidently answer 60 SBA questions across seven body regions, written at a level that tests application rather than naming. You don’t need med-school depth — you need exam-bank depth. That is a meaningful difference. The RCEM Basic Sciences Curriculum is the source of truth for what’s in and what’s out, and it is narrower than a Gray’s Anatomy chapter on the same region.
The seven anatomy sub-domains and how questions distribute
RCEM doesn’t publish a sub-domain mark split for anatomy, but pattern-matching across recent papers (and what high-volume question banks like MRCEM Success, MRCEMexamprep and Pastest emphasise) suggests roughly:
- Upper limb — heaviest sub-domain. Brachial plexus, nerve lesions (radial, median, ulnar), shoulder joint, anatomical snuffbox, carpal tunnel.
- Lower limb — second heaviest. Femoral triangle, popliteal fossa, common peroneal palsy, ankle joint, dermatomes.
- Head & neck — high yield. Triangles of the neck, thyroid relations, facial nerve branches, scalp layers.
- Cranial nerves & CNS — examined together; cavernous sinus contents, circle of Willis, cranial nerve lesions, spinal cord tracts.
- Thorax — mediastinum, intercostal neurovascular bundle, diaphragm openings, surface markings for chest drains.
- Abdomen — inguinal canal, peritoneal recesses, hernia anatomy, foregut/midgut/hindgut blood supply.
If you only have time to drill three regions hard, make them upper limb, lower limb and head & neck. You will pick up the rest from your question bank.
Why does anatomy feel disproportionately hard?
Because most candidates last did anatomy in pre-clinical years, often five to ten years ago, and the testable level is higher than physiology relative to your starting baseline. Physiology you tend to remember in concept form because you use it daily on the shop floor — preload, afterload, V/Q mismatch, GFR, acid-base. Anatomy you genuinely forgot. So even though the mark weighting is identical (60 each), the revision time anatomy demands is usually greater than physiology, not equal.
Plan for that asymmetry, and read about why candidates routinely underestimate anatomy in MRCEM Primary. A common workable split for someone with three months and a clinical job is 40% of hours on anatomy, 30% on physiology, 15% on pharmacology, 10% on micro + path combined, 5% on EBM.
What about physiology — does it deserve equal weight?
Marks-wise, yes — 60 questions, identical to anatomy. Practice-wise, you can usually move through physiology faster because the concepts overlap with everyday ED reasoning. The six sub-domains (cellular, respiratory, cardiovascular, GI, renal, endocrine) map cleanly onto resuscitation, sepsis, fluid prescribing and DKA management — territory you already think about.
The traps are the textbook-only bits: oxygen dissociation curve shifts, renin-angiotensin-aldosterone in detail, GI hormones (gastrin, secretin, CCK, GIP), and the calcium-PTH-vitamin D axis. Those need flashcards, not just question practice.
How should I split revision hours across the five basic sciences?
Mirror the blueprint, then tilt slightly toward anatomy. Working backwards from a 200-hour total revision budget (a reasonable estimate for a working ST1/ST2 over 10-12 weeks):
- Anatomy — 80 hours (40%). The heaviest because of the catch-up factor.
- Physiology — 60 hours (30%). Match the mark weight; you’ll be faster per hour than anatomy.
- Pharmacology — 30 hours (15%). Memorisation-heavy; spaced repetition works well here.
- Microbiology + Pathology — 20 hours combined (10%). These are 26 marks together; high reward for quick wins on common pathogens and inflammation cascades.
- Evidence-Based Medicine — 10 hours (5%). 10 questions, low ceiling, just learn sensitivity/specificity, likelihood ratios, NNT, study design hierarchy and forest plots.
If you have less time, scale these down proportionally — don’t cut anatomy first, because the marginal return per hour on anatomy is high if you haven’t touched it in years.
Can I pass MRCEM Primary if I’m weak in anatomy?
Not realistically. The Angoff-set pass mark typically hovers in the 60-65% range, meaning you need around 110-117 correct out of 180. If you score zero on anatomy you’ve already lost 60 marks before you start, and you need roughly 110 out of the remaining 120 questions — which means near-perfect on everything else. Nobody does that. People who pass score broadly across all six domains, with anatomy typically their second-strongest behind physiology.
You don’t need to be excellent at anatomy. You need to be competent — recognising what’s being asked, eliminating the two obviously wrong distractors, and picking the better of the remaining two. That’s a much lower bar than “know everything”.
Has the anatomy weighting changed since the FRCEM Primary days?
No. When the exam was renamed from FRCEM Primary to MRCEM Primary in August 2021, the structure and blueprint were preserved. RCEM explicitly treats FRCEM Primary passes from August 2016 onwards as equivalent to MRCEM Primary. Older candidates studying from FRCEM-era resources can use them without worrying that the weighting has shifted. The content map traces back to the 2010 Basic Sciences Curriculum.
What anatomy resources actually map to the blueprint?
Three layers work best:
- Question bank as primary driver — MRCEM Success, MRCEMexamprep or Pastest. Aim for 2,000+ anatomy SBAs over the revision window, ideally two passes.
- Visual reference — TeachMeAnatomy for clean diagrams and Kenhub for short videos. Both are free at the level you need.
- One textbook for gap-filling only — Last’s Anatomy or Snell. Don’t read cover-to-cover; use it when a question reveals a hole.
YouTube channels worth a look: Bromley Emergency Courses has free “5 minutes at a time” anatomy snippets (brachial plexus, cranial nerves) that are perfectly pitched for the exam. Cross-check anything labelled “high-yield” against the actual sub-domain list above before committing time.
How does the pass mark interact with the weighting?
The MRCEM Primary uses the Angoff method to set its cut score (no Standard Error Measurement added, unlike the MRCEM SBA). The pass mark is set per sitting based on item difficulty, so there is no fixed number to chase. There is also no negative marking — guess every question. With 1 minute per question and no penalty for wrong answers, leaving a blank is statistical self-harm.
What this means for anatomy strategy: even on questions where you’re 90% lost, you can usually eliminate one or two distractors on anatomical-region grounds (e.g. “that nerve doesn’t reach this far”) and improve your guess from 1-in-4 to 1-in-2 or 1-in-3. Those marginal gains across 60 anatomy questions are worth 4-6 marks.
FAQ
Is the MRCEM Primary blueprint really 33% anatomy, or is it 40%?
It’s 60 out of 180 questions, which is 33.3%. The “40%” figure circulating on Reddit and some prep blogs is incorrect. Together with physiology, however, the two body-of-knowledge domains do make up 66.6% of the paper, which is probably the source of the confusion.
How many anatomy questions are on the actual paper?
60. This is fixed by the RCEM blueprint published in the MRCEM Primary Regulations and Information Pack and has been stable since August 2021.
Which anatomy region appears most often?
Upper limb, based on candidate reports and question-bank distribution. Brachial plexus, peripheral nerve lesions and the shoulder joint are the highest-yield topics within it. RCEM does not publish a sub-domain breakdown.
Is cranial nerve anatomy really worth heavy revision?
Yes. Cranial nerve lesions are a named sub-domain in the blueprint and questions on them are predictable — pupil findings, eye movement defects, facial palsies, lower cranial nerve syndromes. High return on a few hours of focused work.
Can I skip pathology entirely?
You can deprioritise it, but skipping it costs you 9 marks you can’t recover elsewhere. Pathology in MRCEM Primary is narrow (inflammation, immunity, wound healing, basic haematology) and learnable in a weekend. Don’t skip; just don’t over-invest.
What about embryology and histology — are they tested?
Embryology and detailed histology are not listed as sub-domains in the Basic Sciences Curriculum and don’t appear on the paper in a meaningful way. Don’t waste time on them.
How long should I spend revising for MRCEM Primary in total?
Most successful candidates report 10-16 weeks at 12-18 hours per week alongside clinical work, which is 120-280 total hours. Anatomy alone usually absorbs 30-40% of that.
Do I need to know muscle origins and insertions?
Not in pre-clinical detail. You need to know functional groups, innervation, and what gets lost when the nerve is cut. Memorising every origin/insertion is poor return on time.
Is there negative marking?
No. Each correct answer scores 1, each wrong or blank answer scores 0. Always guess.
How is the pass mark determined?
By the Angoff method — a panel of experts rates each question’s difficulty, and the pass mark is set accordingly per sitting. There is no fixed percentage published in advance, but in practice it sits around 60-65%.
Can I sit MRCEM Primary before I start ST training?
Yes. You can sit it in Foundation Year 1 or later. But the pass only counts towards CCT if you enter or re-enter an approved Emergency Medicine training programme within 7 years of passing.
How many attempts do I get?
Six. Previous FRCEM Primary attempts after August 2016 count against this total.
Facts last verified
Blueprint weighting, exam structure, eligibility rules and attempt limits last verified against the RCEM MRCEM Exams page and the MRCEM Primary Regulations and Information Pack (Nov 2023) on .
One next step
If you want a curriculum-mapped MRCEM Primary question bank with the same weighting as the real paper — including a dedicated upper-limb anatomy module — start with the EM Final Exams MRCEM Primary course. Build the 80 anatomy hours into a single 12-week plan and track your sub-domain accuracy weekly. The candidates who pass are the ones who saw their weak region in week 4 and gave it three more hours, not the ones who flattened their revision.
Ready to build your plan? EMF Premium gives you all 40,000 questions and 20 mocks for £59 — one payment, six months' access.