Recognising that four terms belong together can be satisfying. Explaining exactly why they belong together is a more demanding task.
This medical associations quiz contains six original sets spanning physiology, anatomy, pharmacology and immunology. Each has two parts: name the connection, then answer a question that tests how precisely you understand it.
The sets are written for this article and are not copied from a live game. Some categories will be familiar to experienced clinicians. The challenge is to avoid extending a correct association into an incorrect generalisation.
Write your answers before reading the key. A useful response should be more specific than "these are hormones" or "these are medicines".
The six association sets
1. Factor II, factor VII, factor IX, factor X
What is the most useful shared biochemical connection between these four coagulation factors?
Precision check: Does the list contain every vitamin K-dependent protein involved in regulating coagulation?
2. TSH, ACTH, FSH, LH
Name the connection that links the origin and endocrine role of these four hormones.
Precision check: Would "four glycoprotein hormones" also be an accurate category?
3. Oculomotor, facial, glossopharyngeal, vagus
Beyond all being cranial nerves, what functional component links these four?
Precision check: Does the connection mean that each entire nerve is exclusively parasympathetic?
4. Captopril, enalapril, lisinopril, ramipril
Name the pharmacological class and the shared target.
Precision check: Would losartan fit the same precise category simply because it can also lower blood pressure through the renin-angiotensin system?
5. IgG, IgA, IgM, IgE
Name the category and identify the familiar fifth member not included in this four-item set.
Precision check: Which member is associated with physiological transfer across the placenta, and why would "all cross the placenta" be an unsuitable grouping label?
6. Mitral, tricuspid, aortic, pulmonary
Name the common anatomical category, then divide the four terms into two functionally meaningful pairs.
Precision check: Which pair is associated with chordae tendineae, and does that mean the chordae actively pull those valves open?
Answers and explanations
1. Vitamin K-dependent procoagulant factors
Factors II, VII, IX and X are the familiar vitamin K-dependent procoagulant factors.
The word "procoagulant" makes the category more precise. Vitamin K-dependent proteins also include anticoagulant regulators such as proteins C and S, so the four factors are not a complete list of everything vitamin K contributes to coagulation control.
The Linus Pauling Institute's vitamin K review explains the role of vitamin K-dependent modification in enabling relevant proteins to bind calcium, and distinguishes the coagulation factors from regulatory proteins.
The tempting mistake is to turn "these four belong to this category" into "these are the only members of the broader category". A four-tile puzzle often presents a selected set, not an exhaustive physiological inventory.
After identifying the relationship, a useful follow-up question is what the shared dependence explains and what it does not. It provides a biochemical connection; it does not imply identical function or behaviour for each factor.
The daily clinical connections puzzle asks players to make similarly precise groupings across a sixteen-tile board.
2. Anterior pituitary hormones that regulate other endocrine glands
TSH, ACTH, FSH and LH are anterior pituitary hormones with regulatory actions on other endocrine glands. They are commonly described as tropic hormones.
The proposed alternative category, "four glycoprotein hormones", fails because ACTH is a peptide hormone. TSH, FSH and LH are glycoproteins, but the chemical classification does not extend to every member of this set.
OpenStax's pituitary account separates the hormones' source, chemical class and effects.
That distinction is the point of the question. The same four terms can share an anatomical origin and broad regulatory role without sharing every biochemical property.
A learner who remembers only "pituitary hormones" has identified a true but incomplete relationship. A learner who additionally labels all four glycoproteins has overextended an association that fits three members but not the fourth.
Neither error needs to become a broad judgement about the person's endocrinology knowledge. It identifies a specific distinction worth revisiting.
3. Cranial nerves carrying preganglionic parasympathetic fibres
The oculomotor, facial, glossopharyngeal and vagus nerves carry components of the cranial parasympathetic outflow.
The relationship concerns fibres travelling within these nerves. It does not mean that each whole nerve has only a parasympathetic function.
The OpenStax account of autonomic organisation describes the relevant cranial pathways and their connections to ganglia and target organs.
This is a useful example of choosing the correct level of description. A nerve, a fibre population, a nucleus and an end-organ effect are related concepts, but they are not interchangeable labels.
For the precision check, the key answer is therefore "no". Identifying a parasympathetic component does not erase other functions carried by the same named nerve.
A productive follow-up would be to choose one nerve and trace the particular pathway involved, rather than trying to infer every clinical consequence from membership of the group alone.
4. Angiotensin-converting enzyme inhibitors
Captopril, enalapril, lisinopril and ramipril are ACE inhibitors. Their shared pharmacological target is angiotensin-converting enzyme.
The Mayo Clinic's description of ACE inhibitors lists these medicines and explains the class's effect on angiotensin II production.
Losartan belongs to a different class: angiotensin receptor blockers. It therefore does not fit the precise category, even though the drugs can be discussed within the same wider physiological system or used for overlapping purposes.
The example distinguishes a mechanism-based group from an indication-based group. "Medicines used for blood pressure" is too broad to express the intended relationship.
It also shows why recognising a naming pattern is only a starting point. The shared name ending can help someone recognise a class, but it does not establish the dose, suitability or monitoring requirements for a particular patient.
This is an association exercise, not a recommendation to substitute one medicine for another.
5. Immunoglobulin classes, with IgD missing
IgG, IgA, IgM and IgE are immunoglobulin classes. The familiar fifth class absent from the set is IgD.
IgG is the class associated with physiological transplacental transfer. The claim that every member crosses the placenta would therefore be an inaccurate way to define this group.
The OpenStax discussion of B cells and antibodies distinguishes the classes and describes maternal IgG transfer.
Again, a valid four-member group is not necessarily a complete list. A puzzle can select four members of a larger category without implying that the excluded member does not exist.
The application question also matters because a common class label does not imply identical distribution or function. Knowing that these are all antibodies is useful; understanding how their roles differ is the next layer.
For discussion, ask what evidence would be needed before using a result involving one of these classes to make a clinical inference. The label alone cannot supply the patient's diagnosis.
6. Cardiac valves, divided into atrioventricular and semilunar pairs
The mitral and tricuspid valves are the atrioventricular pair. The aortic and pulmonary valves are the semilunar pair.
Chordae tendineae are associated with the atrioventricular valves. They help prevent the valve leaflets from prolapsing backwards during ventricular contraction; they should not be imagined as strings that actively pull the valves open.
OpenStax's heart-anatomy account describes the two groups and their structural differences.
The initial connection, "heart valves", is straightforward. The second task asks whether you can use that broad category to identify a meaningful subdivision.
That is often where an association becomes more useful. The category provides a structure for thinking, but the differences within it explain why two apparently similar anatomical components are not mechanically identical.
For an additional discussion question, describe the direction of flow through each valve in words. That checks the relationship between the name, its position and the movement it permits.
How to review an association you missed
There are several different reasons to miss a group.
You may not recognise one term. You may recognise all four but choose a category that is too broad. You may identify a relationship that fits only three members. Alternatively, you may understand the connection but make an unsupported assumption in the application question.
Those are different learning needs. The response should be proportionate.
An unfamiliar term may justify a brief reference check. A confusion between chemical class and physiological role may need a comparison of the two categories. A correct group followed by a wrong application answer may require a new example that tests how the concept is used.
A broad conclusion such as "I am bad at pharmacology" is less actionable than identifying the precise distinction that was missed.
Turn one answer into a better study question
Take the pituitary set as an example.
A weak follow-up prompt would be "revise pituitary hormones". A more focused prompt would ask: "Which anterior pituitary hormones share a chemical class, and which share a regulatory role without sharing that class?"
The latter separates the two relationships that created the error. It also gives the learner a clear way to check whether the misunderstanding has been resolved.
This is a suggested manual review method. Completing the article does not automatically create a personalised iatroX study plan or diagnose a persistent knowledge gap.
Move from six sets to a full daily puzzle
In clinical connections, the task is to find four groups of four concepts within one board. The relationships are not supplied in advance, so the player must consider how a proposed group fits the remaining terms.
The game provides explanations for the revealed groups and a separate optional application question. The final group completes by elimination, making its explanation worth reading even after a successful finish.
The daily format is mixed clinical science. Today's edition is not guaranteed to cover coagulation, hormones or any of the other subjects used in this article.
Readers who prefer choosing an action can use stat. Those who enjoy identifying a diagnosis through progressive clues can use rounds. Each asks for a different kind of answer.
Frequently asked questions
What makes a medical association precise enough?
It should describe a meaningful relationship that fits every member of the proposed group. A label such as "medical terms" is usually too broad, while a property shared by only three of four items is incomplete.
Can a group be correct without containing every member of the category?
Yes. Four selected immunoglobulin classes or medicines can form a valid group without representing an exhaustive list. The explanation should not imply completeness where none is intended.
Are these six sets taken from clinical connections?
No. They are original exercises written for this article. The daily game uses separate sixteen-tile puzzles with its own explanations and optional application question.
Find the relationships in today's clinical connections puzzle